ALLAN HANCOCK FOUNDATION y/ r? 7 PUBLICATIONS fT Mmon 823-38, 30-40 fms., San Juan Bay, Peru, Februaiy 7, 1938. Two paratypes from Station 833-38, 10 fms., Inde- pendencia Bay, Peru, Februaiy 10, 1938. Remarks. — In the smaller specimens of 2 mm. diameter the rosette was regular and there were 4 rows of scales in each interradius. Only one small scale separated the radial shields proximally. The marginal fence contained only 7 papillae, and the upper arm plates were somewhat tri- angular. The median oral papillae are spiniform and project above the other papillae as in the type. The madreporite is swollen and considerably larger than the oral shields in all specimens. This species can be distin- guished from Ophiophragmiis chilensis Lyman and other members of the genus by the large radial shields, rosette disk, median oral spiniform papilla, and the unique enlarged and swollen madreporite. The name stellatus has reference to the star formed by the large primary plates on the disk. Genus AMPHIGHONDRIUS Nielsen Amphichondrius laevis, new species Plate 4, Figs. 7-9 Description. — Disk diameter, 3.5 mm.; arms, 16 mm. long. Disk pen- tagonal and swollen, covered with large overlapping disk plates that form a rosette. Surrounding the large central disk plate are 5 small triangular plates, which with equally small distal triangular plates separate the 5 large radial plates from one another and from the central plate. There are a few disk scales surrounding the large plates, while the remainder of the disk is covered with moderate-sized, overlapping disk scales. Five or 6 rows of scales in each interradius. On the disk margin, midway between the arms, is a large, conspicuous, elliptical plate, almost twice as wide as long. The disk granulations of the interbrachial spaces below can be seen distal to the marginal plates. Radial shields small, longer than broad, length less than half the disk radius; separated within by one or two disk scales, outer ends in contact. Upper arm plates triangular with broadly rounded angles, proximal margin strongly convex. Basally the arm plates are broader than long; distally they become longer than broad. The plates are separated from one another by the side arm plates, which are finely granulated and meet above and below. Spine ridge large and heavy, bearing 3 stout, erect, subequal arm spines less than an arm segment in length, upper spine stoutest and slightly longest. NO. 2 ZIESENHENNE: NEWOPHIURANS 23 Oral shields small, diamond shaped, about as long as wide, with an angle within and without. Adoral plates broader than long, meeting with- in, separated at the outer ends by the first under arm plate. Jaws small, triangular, depressed medianly. Three oral papillae on a side, outermost largest, rectangular, broader than long, slightly elevated above the jaw; median as long as wide, elevated above the jaw; apical slightly longer than wide, separated from each other and set deeper in the mouth than other papillae. Four teeth, uppermost longest, lowest shortest. All plates of the oral frame and mouth more or less swollen and rounded on the angles. Interbrachial spaces below covered with a dense coat of minute granules; those along the genital slits and disk margin slightly larger. Genital slits long, extending from the oral shields to the disk margin. First under arm plate small, pentagonal, in contact laterally with the adoral plates. Second and succeeding plates pentagonal, slightly wider than long, angle within, proximal lateral margins concave, lateral mar- gins almost straight, distal margin straight, but becoming notched distal- ly, basally all angles rounded. Two rather large tentacle scales, one on the side arm plate, oval, and one on the under arm plate longer than wide; the two are in close contact. Color. — Dried from alcohol, disk light gray with a brownish drab mark centrally on the radial shields and primary plates. Arms light gray, arm spines white. Interbrachial spaces below light tan, mouth parts and under arms dull white. Types. — Holotype, AHF no. 18; 35 paratypes. Type locality. — Station 964-39, 2-8 fms., Tenacatita Bay, Mexico, I\Iay 8, 1939. An additional 13 paratypes as follows: one from Station 209-34, 8-10 fms.. La Libertad, Ecuador, February 9, 1934; 2 from Station 259-34, 12-20 fms., Tangola-Tangola Bay, Mexico, February 28, 1934; 4 from Station 281-34, 35-40 fms., Santa Maria Bay, Lower Cali- fornia, Mexico, March 7, 1934; one from Station 492-36, 35 fms., San Lorenzo Channel, Espiritu Santo Island, Lower California, Mexico, February 19, 1936; one from Station 541-36, 60 fms., Puerto Refugio, Angel de la Guardia Island, Gulf of California; 3 from Station 767-38, 40-50 fms., off Mexico, Lat. 15° 55' N., Long. 97° 41' W., January 9, 1938; and one from Station 770-38, 7 fms., off San Jose Light, Guate- mala, Januaiy 11, 1938. Remarks. — This species differs from Amph'ichondrius granulosus Nielsen in having a disk rosette, upper and under arm plates separated by 24 ALLAN HANCOCK PACIFIC EXPEDITIONS VOL. 8 the side arm plates, radial shields in contact distally, oral shields diamond shaped, granulations on the genital ridge instead of scales with parallel furrows, and triangular-oval upper arm plates little wider than long. The name laevis has reference to the very smooth disk. Genus AMPHIODIA Verrill Amphiodia sculptilis, new species Plate 5, Figs. 1-3 Description. — Disk diameter, 5.5 mm.; arms, 26 mm. long. Disk round and thick, covered with numerous plates. A small pentagonal cen- tral plate and 5 narrow radiating plates form a star on the disk. Between the narrow plates are 5 larger radial plates about the size of the central disk plate. In each interbrachial area are 7 series of long plates, the middle series broadest and overlapping the other series. Numerous small, overlap- ping scales radiate out from the center of the disk. Radial shields rounded triangular, longer than broad, outer and distal margins convex. A small triangular scale separates the shields within, and in some cases smaller elongated plates may separate them. The radial shields in all specimens are separated within by at least one triangular scale; without they are in contact. Sides of disk covered with overlapping scales. Lateral to the geni- tal plate and distal to the radial shield is a series of 3 or 4 minute, blunt, cylindrical spines. Upper arm plates rectangular, almost twice as broad as long, fully in contact with each other, margins straight, distal angles slightly rounded. Side arm plates small, arm spine ridge prominent, bearing 3 short, broad, bluntly rounded arm spines, uppermost slightly largest. Oral shields very small and diamond shaped, an obtuse angle within and truncated without. Adoral plates triangular, broader than long, widest distally, proximal margins concave, the combination of all the adoral plates and oral shields gives the under side a star-shaped appear- ance; within each raylike depression the mouth papillae are located. Jaws small and narrow, bearing 3 oral papillae on a side, outermost largest, flat and triangular; median oval, slightly smaller than others; proximal oblong, twice as long as wide, blocklike, and separated from each other. Five broad teeth, uppermost longest. Interbrachial spaces below covered with uniform overlapping scales that are continuous with the interbrachial scales. Genital slits narrow, bordered by a series of uniform overlapping scales. First under arm plate small, triangular, broader than long. Second and succeeding plates larger, NO. 2 ziesenhenne: newophiurans 25 rectangular, proximal margin convex, distal margin distinctly concave. On the basal under arm plates are 2 longitudinal grooves that divide the plate into a small, oblong center ridge and 2 lateral broader ridges that appear somewhat like supplementary plates, but the plate is not divided. Beyond the disk margin the grooves disappear and the plates are smooth, with parallel lateral margins and convex proximal and concave distal margins. They are fully in contact. One large tentacle scale, longer than wide, widest proximally, almost as long as under arm plate, attached to the lateral margins of the under arm plate. Color. — Dried specimens were pale variegated gray above and dull white below; arms purple gray with irregular white bands. Types. — Holotj'pe, AHF no. 20; 20 paratypes. Type locality. —Station 764-38, 15-20 fms., off White Friar Rocks, Guerrero, Mexico, January 8, 1938. Twenty paratypes as follows: one from Station 121-33, shore, Tenacatita Bay, Mexico, March 16, 1933; 2 from Station 212-34, 45-55 fms.. La Plata Island, Ecuador, February 10, 1934; 3 from Station 259-34, 18 fms., Tangola-Tangola Bay, Mexi- co, February 28, 1934; one from Station 265-34, 5-10 fms., Petatlan Bay, Mexico, March 3, 1934; 2, one in Museum of Comparative Zo- ology, from Station 765-38, 5-10 fms., Chacahua Bay, Mexico, January 9, 1938; 3 from Station 927-39, 4-12 fms., Chacahua Bay, Mexico, March 22, 1939; and 8 from Station 964-39, 2-8 fms., Tenacatita Bay, Mexico, May 8, 1939. Remarks. — This species is closely related to O. violacea Liitken, from which it differs by the single tentacle scale, the grooved under arm plates, and the more complex rosette arrangement on the disk. From O. tabogae Nielsen, it differs by the shape of the radial shields, semi rosette arrange- ment of the disk scales, and the unique under arm plates. The curious sculpturing of the basal under arm plates and the very small oral shields will distinguish this species from any other known member of the genus. The name sculptilis has reference to the characteristic basal under arm plates. Genus OPHIOCNIDA Lyman Ophiocnida californica, new species Plate 5, Figs. 4-6 Description. — Disk diameter, 6 mm. ; arms, 34 mm. long. Disk pen- tagonal, thick, covered with irregular scales radiating from a central primary plate. Scales overlapping, those surrounding the radial shields 26 ALLAN HANCOCK PACIFIC EXPEDITIONS VOL. 8 largest. A number of the plates bear a short, heavy, tapering spinelet. There are from 15 to 20 spinelets irregularly placed on the disk, but they are even more numerous along the sides and margin of the disk. Radial shields long and narrow, about 3 times as long as broad, separated by a series of scales proximally, distal half fully in contact. Surface of radial shields finely granulate. Genital plates in contact with the distal margin of the radial shields and visible from above. Upper arm plates triangular, twice as broad as long, an obtuse angle proximally, sides slightly convex, distal margin variable according to the number of pieces in the upper plate. Upper plates variable, sometimes in a single piece but often 2 distinct lateral sections and from one to 6 median pieces, usually one small triangular piece distally, 2 small median triangu- lar pieces or often additional pieces proximally. The upper plates are in contact basally, but distally they become separated by the side arm plates. Side arm plates with a prominent spine ridge bearing 3 heavy, tapering, bluntly tipped arm spines. Middle spine longest, about as long as an arm segment. Spines on the first arm plate very short and stubby; they gradu- ally increase in length to the 6th arm segment, from whence they are more or less uniform distally. Oral shields diamond shaped, slightly wider than long, with an acute proximal angle. Adoral plates twice as broad as long, meeting within, widest distally. Jaws long and narrow. Three oral papillae on a side, outermost rectangular, longer than wide, with a serrate cutting margin ; apical blocklike, well separated, longer than broad, cutting edges concave; median heavy, triangular, about as long as wide. Four broad, flat teeth, lowermost shortest, uppermost longest. No tooth papillae. Interbrachial spaces below covered with thick, overlapping, crowded scales, a few bearing short, hea\y, sharp spinelets, irregularly distributed. Genital slits bordered by a series of scales. First under arm plate small, longer than wide, with an acutely convex distal margin. Second and suc- ceeding plates pentagonal, wider than long, with an obtuse proximal angle and straight lateral and distal margins. Plates barely in contact basally, separated distally by the large, coarsely granulated side arm plates. Two long, narrow tentacle scales attached on the distal side of the tentacle pore. Color. — Dried specimens had dark cream-colored disks with darker radial shields. Arms pinkish buff with irregular maroon bands and mark- ings. Interbrachial areas below and mouth parts grayish white, under arms pinkish buff with no banding. NO. 2 ZIESENHENNE: NEWOPHIURANS 27 Types. — Holotype, AHF no. 13; 15 paratypes. Type locality. — Holotype and 5 paratypes from Station 529-36, 165 fms., off San Francisquito Bay, Lower California, March 1, 1936, Ten paratypes as follows: 2 from Station 526-36, 3-5 fms., off Mangles Anchorage, Lower California, February 28, 1936; 5 from Station 534- 36, 125 fms., off San Francisquito Bay, Lower California, March 2, 1936; and 3 from Station 750-37, 60 fms.. Outer Gorda Bank, Lower California, April 4, 1937. Remarks. — In the smaller specimens the dorsal arm plates are not divided. O. calif ornica can be distinguished from O. hispida (Le Conte) by the oral shields, which are about as long as broad ; the outermost oral papilla, which is longer than broad ; radial shields half in contact ; upper arm plates triangular, divided into several pieces in the adults; and the arm length, which is 5 times the disk diameter, while the arm length of O. hispida is 10 times the disk diameter. From the other members of the genus, O. calif ornica can be readily distinguished by the unique upper arm plates and the oral shields. It has been named calif ornica, as the range of this species seems to be confined to the Gulf of California. Genus AMPHIOPLUS Verrill Amphioplus philohelminthius, new species Plate 5, Figs. 7-9 Description. — Disk diameter, 4 mm.; arms, 51 mm. long. Disk small, pentagonal, with a central and 5 radial primary disk plates ; disk covered with small uniform scales, those bordering the radial shields larger. Radial shields large, the length more than half the disk radius, about 3 times as long as broad, slightly separated proximally but in contact dis- tally ; somewhat swollen and raised above the remainder of the disk. First upper arm plate wider than long. Succeeding plates oval, slightly wider than long, becoming more so distally, widest proximally, with a convex margin, distal margin sharply rounded. At the arm extremities the plates become longer than wide and rounded pentagonal or triangular. The plates are separated by the side arm plates throughout the arm length. Side arm plates 3 times as broad as long, separated from each other by a naked membrane. Spine ridge prominent, bearing 4 flattened, lanceo- late, blunt-tipped spines on the 10 basal arm segments, 3 subequal spines on the remainder of the arm, median spines shorter than upper and lowermost. 28 ALLAN HANCOCK PACIFIC EXPEDITIONS VOL. 8 Oral shields about as long as broad, the inner half much wider than the outer half, proximal margins broadly rounded, lateral margins con- cave, distal and truncate. Adoral plates triangular, twice as broad as long, widest distally, not quite meeting within. Jaws long and narrow. Four oral papillae on a side, apical largest, rounded and blocklike, longer than wide, tapering slightly proximally to give a triangular appearance to some specimens; other papillae flat and rounded, longer than broad, outermost slightly largest. Four bluntly rounded, broad teeth, lower- most shortest, uppermost longest. Interbrachial spaces below covered with small overlapping scales distally, but fewer proximally. Genital slits very large, bordered by large and wide genital plates. First under arm plate triangular, longer than wide, lateral margins deeply concave producing lateral lobes, distal mar- gin convex. Succeeding plates rectangular, longer than wide, lateral margins parallel, distal margin concave, proximal margin convex. Dis- tally the proximal margins are produced in a right angle, and near the arm extremities the plates become triangular. Basally the plates are in contact, but distally they become separated by the side arm plates. Tenta- cle scales, 2 on the basal pores, but the one on the under arm plate is exceedingly small and soon disappears altogether. Color. — In dry specimens the disk and arms are light gray with faint brown markings on the arms. Mouth parts and under arms light yellow. Types. — Holotype, AHF no. 6; 32 paratypes, 16 in M.C.Z. Type locality. — Station 823-38, 30-40 fms., San Juan Bay, Peru, February 7, 1938. An additional paratype in the Museum of Compara- tive Zoology from Station 826-38, 20-30 fms., San Juan Bay, Peru, February 7, 1938, and one from Station 833-38, 8 fms., Independencia Bay, Peru, February 10, 1938. Remarks. — This species lives in great numbers in a soft mud which teems with small, white nematode worms, a most repulsive environment, to which, however, it is well adapted by its small flat disk and long, very slender arms. It is the first Amphioplus to be reported from the western coast of South America and differs obviously from the 3 species from the Panamic region described by Lutken and Mortensen in 1899. The oral papillae and disk scaling are quite distinctive. The species has been named philohelminthius because of its fondness for living with little worms. NO. 2 ziesenhenne: newophiurans 29 Ophiochitonidae Genus OPHIONEREIS Lutken Ophionereis dictyota, new species Plate 6, Figs. 1-5 Description. — Disk diameter, 9 mm. ; arms broken, longest about 67 mm. long. Disk covered with thick and overlapping scales which become thicker surrounding the radial shields. Extending interradially from the radial shields, at the margin of the disk, is a series of 6 to 8 large, distinct scales, about Yz as long as the length of the radial shields. Radial shields small and pennantlike, about 3 times as long as broad, proximally finely pointed, distally rounded, surrounded by large disk scales. First upper arm plate small, oval, proximal margin concave, distal convex. Second plate hexagonal, twice as large as the first; third and suc- ceeding plates larger. The plates are hexagonal, broader than long, fully in contact. Proximal and proximal lateral margins concave, distal lateral margins convex, distal margin nearly straight. Supplementaiy plates longer than wide, inner margin concave, outer margins convex to form a distinct, rounded, outer distal angle. Side arm plates separated from each other by a soft membrane. Each plate bears 3 rounded, tapering and slightly curved, blunt-tipped arm spines, slightly longer than an arm segment, the median longest. Upper spine flat, blunt and little curved. Oral shields oval, longer than wide, proximally convex, distal lateral margins concave. Adoral plates lanceolate, wider than long, enlarging distally with a rounded margin, not meeting within. Jaws long and nar- row. Four or 5 oral papillae on a side, outermost flat and triangular; others blunt and angular, almost rounded ; apical smallest, shorter than others. Four broad and rounded teeth, lowermost shortest and thick, uppermost thin and long. Interbrachial spaces below densely covered with fine overlapping scales. Genital slit ridge bears numerous fine stumps, longer than broad proximally, becoming shorter and fewer distally. First under arm plate quadrangular, proximal margin narrow and concave, lateral margins almost straight, and distal margin decidedly rounded. Second plate much larger, square, proximal margin little concave, plates only ^ in contact, distally even less so. One large, oval, flat tentacle scale, almost ^ the length of under arm plate. Color. — Dried specimens had a cream-colored disk, reticulated with brown markings which continue to the oral shields. Proximally between 30 ALLAN HANCOCK PACIFIC EXPEDITIONS VOL. 8 the genital slits is a dark brown triangular splotch. Arms light buff with a wide (2 segments), dark brown, almost black band, every 3 to 4 seg- ments. Mouth parts and arm spines cream colored, slight traces of the upper arm bands continue below. Types. — Holotype, AHF no. 7; 5 paratypes. Type locality. — Station 778-38, tide pool, Chatham Bay, Cocos Island, Costa Rica, January 14, 1938. Five paratypes from Station 445- 35, shore, Panama City, Panama, February 2, 1935 ; one from Station 447-35, coral, Secas Islands, Panama, February 4, 1935 ; one from Sta- tion 512-36, shore, Ballena Bay, Espiritu Santo Island, Gulf of Califor- nia, February 23, 1936; one from Station 515-36, shore, San Francisco Island, Gulf of California, Februarj^ 24, 1936; and one from Station 522-36, tide pool, Agua Verde Bay, Lower California, Mexico, Febru- ary 27, 1936. Remarks. — In life the holotype had a bluish gray disk, reticulated with light brown, much as in the West Indian O. reticulata (Say). The very long arms, which were much broken in capturing the specimen, were broadly banded with dusky purple. This species differs from other eastern Pacific Ophionereis by the irregular coarse disk scaling, a uniform series of 5 or 6 large marginal disk scales extending interradially from the radial shields, large radial shields, and the distinct coloring of the arms and disk. The name dictyota has been chosen because of the reticu- lations on the disk. Ophionereis perplexa, new species Plate 7, Figs. 7-9 Description. — Disk diameter, 8 mm. ; arms, 42 mm. long. Disk more or less depressed and irregular because of shrinkage upon drying. The disk is covered by a membrane, which upon drying shows minute, dense, overlapping, uniform scales, visible only under high magnification. No primaiy plates are visible, and the scales bordering the radial shields and disk margins are not enlarged or conspicuous. Radial shields small, nar- row, more than 4 times as long as broad, acutely pointed within, widely separated, distance apart exceeding the length of radial shields. The minute overlapping scales obscure the outline of the radial shields. First upper arm plate small, semilunar, wider than long, proximal margin straight, distal margin broadly convex, overlapping next plate. Succeeding plates large, wider than long, basally triangular with rounded corners, proximal margin slightly concave, distal margin convex, less NO, 2 ZIESENHENNE: NEWOPHIURANS 31 than half the width of proximal margin ; distally the plates become pen- tagonal or hexagonal with slightly concave proximal and proximal lateral margins and convex distal margins. Supplementary plates triangular, distal margins convex and bearing a series of parallel minute ridges con- spicuous under high magnification. Plates ys to }^ the size of upper arm plates. Side arm plates wide, not meeting above or below, spine ridge prominent, bearing 3 large, heavy, broad, bluntly tipped arm spines; 1^ to 2 arm segments long, middle spine longest, uppermost the shortest. Oral shields triangular, wider than long, obtuse angle within, lateral angles convex. Adoral plates narrow, not meeting within, broader dis- tally. Jaws small and triangular. Four oral papillae on a side, outermost bluntly pointed, longer than wide; next 2 broad, rounded, and heavy; apical heavy, blunt, and rounded, slightly longer than broad. In the holotype and a few paratypes the 2nd outermost papilla is divided into 2 or 3 fine spiniform papillae with a common base. Four broad and rounded teeth, uppermost longest. Interbrachial spaces below covered by a thin membrane, which under high magnification shows very minute scales. Genital slits large and wide ; a few scales can be seen, but no genital papillae are present. First under arm plate small, slightly longer than wide, distal margin convex, lateral and proximal margins almost straight. Second and succeeding plates large, longer than wide, proximal and distal margins convex, lateral margins almost straight, plates in contact with each other. One large, oval tentacle scale, half the length of under arm plate, attached to the side arm plate. Color. — Dried specimens, disk pale yellow with reticulating purplish lines; above the arm base and between the radial shields is a purple-brown area spotted with cream yellow that blends in with the reticulations of the disk proximally. Upper arms greenish gray with a purple band one segment wide, continuing below and spaced about 3 to 5 arm segments apart. The supplementary plates on each side of the purple band are creamy white. Arm spines are gray with a white base and a transverse purple band above the base and on the tip. Mouth parts and under arm plates are creamy white with the purple arm bands extended from above. Disk below is a brown orange in the naked membrane with the disk colors and reticulations extending onto the interbrachial area. Types. — Holotype, AHF no. 4; 88 paratypes. Type locality. — Holotype and 3 paratypes from Station 333-35, shore, James Island, Galapagos, December 11, 1934. Eighty-five addi- tional paratypes as follows: one from Station 73-33, shore, Cartago Bay, 32 ALLAN HANCOCK PACIFIC EXPEDITIONS VOL. 8 Albemarle Island, Galapagos, February 13, 1933; 2 from Station 202-34, shore, Osborn Island, Galapagos, January 31, 1934; one from Station 313-35, shore, Black Beach Anchorage, Charles Island, Galapagos, De- cember 6, 1934; 3 from Station 342-35, shore, Bartholomew Island, Ga- lapagos, December 12, 1934; 12 from Station 350-35, shore. South Sey- mour Island, Galapagos, December 13, 1934; 7 from Station 351-35, shore, Charles Island, Galapagos, December 14, 1934; one from Station 515-36, shore, San Francisco Island, Gulf of California, Februaiy 24, 1936; 6 from Station 530-36, 10-20 fms., ofif San Francisquito Bay, Low- er California, Mexico, March 1, 1936; 2 from Station 719-37, 10-25 fms., Consag Rock, Lower California, Mexico, March 24, 1937; 5 from Station 782-38, shore, Darwin Bay, Tower Island, Galapagos, January 16, 1938; 29 from Station 784-38, shore. Tower Island, Galapagos, Jan- uary 17, 1938; 3 from Station 789-38, shore. South Seymour Island, Galapagos, January 19, 1938; one from Station 795-38, 30-40 fms., Sulivan Bay, James Island, Galapagos, January 21, 1938; 2 from Station 796-38, shore, Sulivan Bay, James Island, Galapagos, January 21, 1938; 4 from Station 800-38, shore, Cartago Bay, Albemarle Island, Galapagos, January 22, 1938; 3 from Station 803-38, shore. Black Beach, Charles Island, Galapagos, January 23, 1938; one from Station 808-38, shore, Academy Bay, Indefatigable Island, Galapagos, January 25, 1938; and 2 from Station 400-35, shore, Manta, Ecuador, January 19, 1935. Remarks. — This species is rather common in the Galapagos Islands and differs from the other members of the genus by its exceedingly fine disk scaling, radial shields which are separated more than their length apart, lack of genital papillae, absence of enlarged scales about the disk margin and radial shields, and coloring. From O. annulate (Le Conte) and O. dictyota it differs by lacking large disk scales about the radial shields and disk margins. Its 3 arm spines distinguish it from O. albo- maculata Smith and O. eurybrachtplax H. L. Clark, which basally have 4. From its closest ally, O. nuda Liitken and Mortensen, it can be dis- tinguished by its arm length, 4 oral papillae, presence of fine scales, lack of genital papillae, and uniquely separated radial shields. In a series of 64 are a number of variations ; in some specimens the disk below is cov- ered by a naked membrane, and in others the upper disk scaling is continu- ous to the adoral plates. Of the 64 specimens, 45 had 4 oral papillae on each side ; 7 had 3 on one or more jaw sides and 4 on the remaining sides ; and 4 had 4 oral papillae with either of the 2 middle papillae divided into 2 or 3 spiniform papillae, with a common base. The name perplexa has NO. 2 ZIESENHENNE : NEW OPHIURANS 33 been selected because of the difficulty of distinguishing this species from other Pacific forms. OPHIODESMUS, new genus Similar to Ophionereis, but the disk scaling is coarse and compacted to such a degree that only a small portion of some of the disk scales is visible. The supplementary arm plates are very small, confined mainly to the side of the arm and not conspicuous from above. Upper arm plates oval, slightly wider than long. This genus seems to be a connecting link between Ophionereis of the Ophiochitonidae and Ophiactis of the Amphi- uridae. Since it shows characteristics of both families and the under side is decidedly similar to Ophionereis, this genus is placed in the Ophiochi- tonidae. The name Ophiodesmus has reference to its connecting-link po- sition between Amphiuridae and Ophiochitonidae. Genotype: Ophiodesmus aniphilogus, new species. Ophiodesmus amphilogus, new species Plate 9, Figs. 4-6 Description. — Disk diameter, 4.5 mm. ; arms, short and slender, grad- ually tapering, about 11 mm. long. Disk circular and flat, covered by numerous compacted, overlapping, irregular scales. Some of the scales are compacted and overlap to such an extent that only an elliptical portion or narrow margins are exposed. Surrounding the larger scales are several irregularly placed smaller scales. There are 7 to 9 irregular series of scales in each interradius. Primary plates are not conspicuous. Radial shields small, oval shaped, about twice as long as wide, widely separated, about their length apart, by several large and numerous small disk scales. Length of shields about 54 of the disk radius. First upper arm plate small, wider than long, distal margin convex. Second plate oval shaped, larger than the first, slightly wider than long, distal margin strongly convex. Third and succeeding plates larger, oval shaped, basally wider than long, distally becoming longer than wide, mar- gins convex. Basally the plates overlap; distally they become separated by the side arm plates. Under high magnification the upper arm plates appear smoother in texture than the side arm plates. Side arm plates wider than long, spine ridge produced and prominent, bearing 3 heavy, flattened, broad, short, subequal arm spines, as long as an arm segment basally, and gradually reducing in length distally to the arm tips where they are 34 ALLAN HANCOCK PACIFIC EXPEDITIONS VOL. 8 only y3 the length of the arm segment. Median spine slightly the longest ; upper spine heaviest and blunt. Supplementary arm plates small and tri- angular, about i/io the size of the upper arm plate; inner margin concave, distal and outer margins convex. The supplementary plate is inserted under the upper and proximal side arm plates and overlaps the distal side arm plate. Oral shields triangular, about as long as broad, inner margins almost straight. Adoral plates triangular, broader than long, widest distally, meeting within, inner margin slightly concave, other margins straight or slightly concave. Jaws small, triangular. Four oral papillae, about equal in length, on a side. Outermost largest, flat, longer than broad, cutting margin rounded. Inner 3 papillae narrow, flat, longer than broad, bluntly pointed ; inner pair heaviest. Distal to the outer papillae is the first ten- tacle scale, set deep in the mouth, which might easily be taken for an oral papilla. Four broad teeth of equal length, cutting margins convex. Interbrachial spaces below covered with unequal, overlapping, crowd- ed scales. The largest scales are centrally located ; those along the genital slits are smaller and crowded so only a portion of the scales are visible. Genital slits short, equal in length to 2 arm segments. First under arm plate small, longer than broad, distal margin convex. Second and suc- ceeding plates large, octagonal basally, triangular distally, longer than wide; proximal lateral margins straight, lateral margins concave, distal margins broadly convex. Plates in contact basally, separated distally by the side arm plates. One large, oval tentacle scale, longer than wide, not quite half the length of the under arm plate, attached to the side arm plate. Color. — Dried from alcohol, disk white with dark gray circles at the arm base. Arms dark gray with irregularly spaced white and light gray bands. Under side white with irregular gray bands on the arms. Two of the paratypes differ by having the disk uniformly mottled with white, light and dark gray. Arms irregularly banded with white, light and dark gray. Under side white with several gray bands on the arms. Types. — Holotype, AHF no. 22; 3 paratypes. Type locality. — Station 287-34, 10-15 fms., Cerros Island, Lower California, Mexico, March 10, 1934. Remarks. — This species differs from Ophionereis annulata (Le Conte) of equal size in its coarser disk scaling, lack of genital papillae, arm length twice the disk diameter, and exceedingly small supplementary plates. From the young of Ophionereis eurybrachiplax H. L. Clark, it NO. 2 ZIESENHENNE : NEW OPHIURANS 35 differs in having only 3 basal ann spines, shorter and stouter arm spines, arms only twice the disk diameter, as compared to 5 times the disk di- ameter, small, oval upper arm plates as compared to large, broad, rec- tangular upper arm plates. The above characteristics distinguish this species from other known related forms. In color it differs from Ophio- nereis, which has regularly dark banded arms. The name amphilogus has reference to the doubtful position of this species. Ophiolepididae Genus OPHIOMISIDIUM Koehler Ophiomisidium leurum, new species Plate 7, Figs. 1-3 Description. — Disk diameter, 4 mm.; arms, 4 mm. long. Disk large; arms short, tapering rapidly. Disk covered with 37 large, granulated plates. Central plate pentagonal, surrounded by 5 quadrangular plates, whose acute distal angles separate the proximal portion of the radial shields. Separating the radial shields interradially are 2 plates, a rectan- gular proximal plate and, distally, a produced, rounded, swollen plate that fills the interbrachial margin and side of the disk. A rounded plate and an oblong plate separate the distal margins of the radial shields. A small plate (distal end of 2nd side arm plate) at the distal margin of each radial shield, bearing 3 large spines, completes the side margins of the disk. Radial shields oblong, almost twice as long as wide, separated proxi- mally by the primary radial plate, broadly in contact medially but sep- arated distally by 2 plates, one rounded and swollen above the surface of the radial shields, the other much broader, not elevated, lying on the side arm plates at the arm base. First upper arm plate very small, diamond shaped, succeeding plates becoming still smaller distally until none can be found after the 4th arm segment; plates widely separated by the side arm plates. First side arm plates somewhat swollen, wider than long, meeting within, not visible from above; 2nd plates are visible from above just distal to the radial shields. Succeeding side arm plates narrower, becoming longer distally and fully in contact. There are apparently not more than 10 or 12 arm segments. Arm spines small, only 2 on first arm segment; there are 3 on the next arm segment, well separated, uppermost heaviest, triangular, blunt, longer than wide, median one or 2 shorter, lowermost shortest, 36 ALLAN HANCOCK PACIFIC EXPEDITIONS VOL. 8 slightly tapering. Three uniform short arm spines on next 2 arm seg- ments, blunt and uniformly tapering. Two very short and peglike arm spines on the remaining arm segments. Oral shields diamond shaped, longer than broad. Adoral plates dia- mond shaped, slightly broader than long, meeting fully within. Jaws quadrilateral, longer than broad. Four oral papillae, broad and blocklike, broader than long, their outlines cannot be seen distinctly. Interbrachial spaces below covered by 2 long, narrow plates, distal of the oral shields, and separated at the disk margin by a triangular plate, the acute angle within and a broadly rounded margin without that ex- tends beyond the disk margin, appearing much like a horizontal keel on the large interbrachial plate. Genital slits not visible. First under arm plate large, shield shaped, succeeding plates similar but becoming smaller distally, disappearing entirely on the 6th arm segment. Under plates widely separated by the side arm plates. Tentacle scales only on the basal 5 arm segments, 2, sometimes 3, small oval tentacle scales on each pore. Color. — All specimens dried from alcohol are bleached nearly white. Types. — Holotype, AHF no. 16; 3 paratypes, one in M.C.Z. Type locality. — Station 810-38, 73 fms., off Barrington Island, Gala- pagos, January 26, 1938. Paratypes: one from Station 767-38, 45 fms., off Chacahua Bay, Oaxaca, Mexico, January 9, 1938; and 2, one in the Museum of Comparative Zoology, from Station 792-38, 75 fms., off Daphne Minor Island, Galapagos, January 20, 1939. Remarks. — This little brittle star differs markedly from other known members of the genus by its smooth, flat disk with 10 marginal knobs (or at least elevations) on the 5 radial and 5 interradial marginal plates. The name leurum has been selected with reference to the very flattened form of the entire body. Genus AMPHIOPHIURA Matsumoto Amphiophiura irregularis, new species Plate 7, Figs. 4-6 Description. — Disk diameter, 7 mm.; vertical diameter, 1.3 mm.; arms, 18 mm. long. Disk pentagonal, flat, composed of 24 flat plates, including the radial shields; 8 irregular plates surround the central plate, a large oblong interradial plate separates the radial shields. The number of disk plates ranges from 20 to 26, including radial shields, in the 16 NO. 2 ZIESENHENNE : NEW OPHIURANS 37 paratypes. A central plate is sometimes found, but a symmetrical rosette has not been seen in the 17 specimens. In several specimens radial shields and interradial plates are in contact with the central plate at one point. Interbrachially is a large, transversely oval plate in contact with the inter- radial plate and separated from the radial shields by one or 2 smaller plates. Radial shields large, hexagonal, about half the disk radius, slightly longer than wide, broadly in contact. First upper arm plate small, triangular, with the peak within, bearing 2 to 5 fine spinelets on each lateral margin along the genital slit. Second plate hexagonal, swollen, broader than long, distal and proximal margins straight, lateral margins little concave, bearing 4 to 8 fine spinelets along the genital slit. Third plate hexagonal, about as long as broad, swollen, with straight proximal and distal margins. Succeeding plates pentagonal, then quadrangular, becoming triangular distally, longer than broad, lat- eral margins straight, distal margins convex. Basal 8 plates in contact, distally they become farther separated by the side arm plates until they are reduced to ^ the length of an arm segment at the extremities. All plates are finely granulated. First side arm plate greatly reduced, bearing 2 short, broad tentacle scales and 2 long, conical arm spines on the genital slit. Third plate slightly larger, bearing 3 short, broad tentacle scales and 4 long, slender, pointed, well-spaced arm spines along the genital slit. Fourth to 8th plate bearing 2 small, flat, long tentacle scales or modified arm spines, succeeding plates bearing only one. Fourth and succeeding plates bear 5 then 4 long, finely tapering, well-spaced arm spines, about Yz the length of the arm segment, median spine longest, upper and lower- most shortest. Oral shields large, occupying the interradius below, oval, longer than wide, with an acute angle within and broad, convex lateral and distal margins. Adoral plates quadrangular, little broader than long, meeting within. Jaws wider than long, scarcely larger than adoral plates. Four or 5 oral papillae on a side, outermost twice as broad as long; next broader than long; next delicate, longer than broad, apical broad, heavy, pointed, longer than broad. Three narrow pointed teeth, undermost shortest. Interbrachial spaces below covered by the large, oval oral shields and 2 or more small interbrachial plates. Genital slits long, extending from the adoral plates to the radial shields. Genital plates long and narrow, in contact with the distal margin of the radial shields; each plate bears a comb of 18 to 26 fine, long, tapering, pointed spines, well separated at their bases, lowermost becoming shorter and blunt. First under arm plate 38 ALLAN HANCOCK PACIFIC EXPEDITIONS VOL.8 largest, longer than wide, proximal margin convex, distal margin deeply concave; lateral margins concave, bearing 3 or 4 reduced tentacle scales, outermost being the largest. Second plate rectangular, broader than long, proximal margin almost straight, distal margin concave, lateral margins bearing 2 short, broad tentacle scales. Third plate rectangular, only slightly broader than long, lateral margins bearing 2 short tentacle scales, outermost largest. Fourth to 8th plates hexagonal, much wider than long; 4th, 5th, and 6th bearing a minute tentacle scale on the distal lateral angle. Succeeding plates pentagonal or oblong, small, becoming triangular and smaller distally, until they occupy only %. of the arm segment or less at the extremities. The 6 basal plates are separated by a deep concavity, succeeding plates separated by side arm plates; distally the separation be- comes even greater. Color. — Dried from alcohol, disk white with a lavender tinge, arms light cream color. In life, upper surface variegated with light and dark red, or red and yellowish, or red and white; oral surface white. The larger specimens are not deeply colored. Types. — Holotype, AHF no. 12; 60 paratypes, 16 in M.C.Z. Type locality. — Holotype and 33 paratypes, 16 in the Museum of Comparative Zoology, from Station 792-38, 70-80 fms., off Daphne Minor Island, Galapagos, January 20, 1938; 2 paratypes from Station 191-34, 70 fms., Lat. 0° 55' S., Long. 90° 39' W., January 26, 1934; and 25 paratypes from Station 190-34, 58-60 fms., Lat. 0° 55' S., Long. 90° 30' W., January 26, 1934. Remarks. — This species is closely related to A. paucisquama but dif- fers as f ollovi^ : A. irregularis No symmetrical rosette on disk All plates finely granular Plates flat or slightly swollen Radial shields large Disk flat, 1.5 mm. thick Arms about 2.2 times disk diame- ter, not slender distally A. paucisquama A symmetrical rosette on the disk composed of a central pentago- nal plate and 5 larger, equal ra- dial plates Disk and basal arm plates deeply pitted Plates convex, basal upper arm plates almost hemispherical Radial shields small Disk elevated, 3.5 mm. thick Arms short, 1.8 times disk diame- ter, becoming very slender dis- tally .f NO. 2 ZIESENHENNE: NEWOPHIURANS 39 The name irregularis has been chosen for this species because of the irregular arrangement of the disk scales. Amphiophiura paucisquama, new species Plate 8, Figs. 1-3 Description. — Disk diameter, 7 mm.; thickness of disk, 3.5 mm.; arms, 13 mm. long. Disk large, arms relatively short, tapering rapidly. Disk covered with 21 very large pitted plates including the radial shields. A large, swollen, pentagonal central plate is surrounded by 5 slightly larger plates that are in contact with the single, large, interradial plate and the radial shields. The interradial plate is pentagonal with the proxi- mal margins concave, forming a peak, lateral and distal margins almost straight. Viewed under an ordinary hand lens all plates are deeply pitted, resembling the mesh on a golf ball. Radial shields much smaller than disk plates, pentagonal, fully in contact, decidedly broader than long, deeply pitted as other disk plates. First upper arm plate oval, broader than long, fully in contact with the second arm plate and radial shields, lateral margins bear genital slit papillae. Distally the plate bears an elevated transverse ridge which is deeply pitted. Second plate oval, broader than long, with a high convex surface, deeply pitted, in contact with the first upper arm plate. Third plate oval, slightly broader than long and rather high, elevated to re- semble a golf ball, deeply reticulated. Succeeding plates diamond shaped, becoming smaller, flatter, and more widely separated by the side arm plates distally. Side arm plates twice as broad as long, swollen, in contact below from the 5th arm segment out and in contact above from the 3rd segment out. Three short, peglike arm spines about Yz the length of the side arm plates, widely separated, upper longest and heaviest, under short- est. The arm plates are separated from each other or appear that way be- cause of the prominent spine ridge. All plates are deeply pitted by an irregular reticulation similar to that on golf balls. Oral shields large, triangular, truncated within and broadly convex without, longer than wide, occupying the entire ventral interradius. Ad- oral plates small, diamond shaped, fully in contact and separated from the oral shield by a furrow. Jaws diamond shaped, twice as long as wide. Four or 5 oral papillae on a side, outermost largest, rectangular, broader than long; 2nd and 3rd outermost rectangular, only slightly broader than long. Inner papillae ovate, pointed, flat, longer than broad. Three bluntly rounded teeth. 40 ALLAN HANCOCK PACIFIC EXPEDITIONS VOL. 8 Interbrachial spaces below covered by the large oral shield surrounded by a few smaller plates. In the interbrachial area is a large plate in con- tact with the oral shield and the upper interradial plate. First under arm plate large, slightly longer than wide, with a convex proximal margin and concave distal margin, widely separated from the 2nd under arm plate by a groove. Second plate rectangular, 3rd and succeeding plates longer than broad, becoming diamond shaped distally, reduced in size and far- ther separated by the side arm plates, which meet below between the 4th and 5th under arm plates. The first 5 arm plates are separated below by a deep groove. Plates swollen and deeply pitted. Genital slits large, extend- ing from the radial shields to the adoral plates. Thirteen to 18 spines on the genital ridge, those above long, blunt, and well spaced, undermost become shorter, broader, flatter, and compacted. Three broad, flat ten- tacle scales, outermost largest on 1st under plate. Two broad, flat ten- tacle scales on the adoral plate. Three flat, broad tentacle scales on the 2nd and 3rd under plates. Three broad flat tentacle scales on the 1st and 2nd side arm plates. Two tentacle scales on the next 3 under arm plates and then only one for 3 plates before disappearing. Two tentacle scales on the 3rd to 5th side arm plate and then only one to the end of the arm. Color. — Dried from alcohol, white with a lavender tinge, stained brownish drab about the base of the arms. Types. — Holotype, AHF no. 8; 13 paratypes, 5 in M.C.Z. Type locality.— ^t?iX.\on 818-38, 300 fms., south of Hood Island, Galapagos, January 20, 1938. Thirteen additional parat^Tes, 5 in the Museum of Comparative Zoology, from Station 786-38, 392 fms., N.E. of Indefatigable Island, Galapagos, January 18, 1938. Remarks. — The thick rounded disk, short rapidly tapering arms, sym- metrical disk rosette, and unique deep pits on the primaiy plates, espe- cially the basal upper arm plates, which resemble the mesh on a golf ball, easily distinguish the adults of this species from other known members of the genus. Unfortunately, in small specimens the pitted surface is not noticeable under an ordinary lens but requires a magnification of 40 diameters or more. It approaches Stegophiura in the shape of the arms, but the disk scales and arm spines are more like Amphiophiura. This species has been named paucisquama in reference to the small number of disk plates. NO. 2 ziesenhenne: newophiurans 41 Genus OPHIOLEPIS Muller and Troschel Ophiolepis plateia, new species Plate 8, Figs. 4-6 Description. — Disk diameter, 13.5 mm.; arms, 38 mm. long. Disk covered with large primary plates, each surrounded by a row of single smaller, regularly arranged scales. Disk very flat and depressed; 2 rounded protruding plates on the interbrachial margin, most conspicuous from the under side. Arms flat, tapering distally; base of arm 4.5 mm. wide, width midway of the arm only 2.5 mm. Radial shields large and distinct, longer than broad, separated from each other and interradially by a primary plate or plates, each surrounded by a single row of small disk scales. Upper arm plates rectangular, wider than long basally, becoming tri- angular distally and longer than wide; lateral margins convex basally, concave distally, distal margin concave basally, almost convex distally. Basally 2 triangular supplementaiy plates are inserted between the upper ends of the side arm plates ; distally they are replaced by a single supple- mentaiy plate. Side arm plates large, separated above by the supplemen- taiy plates. There are 4 short, blunt, conical, well-spaced arm spines basally, but only 3 distally, placed low down on the side arm plates. Arm spines less than half the length of arm segment. Oral shields narrow, twice as long as wide, proximal angle acute, lateral margins concave, distal margin convex. Adoral plates rectangular, widest without, meeting within, slightly prolonged between the oral shield and the inner side arm plate. Jaws triangular, longer than wide, smaller than the adoral plates. Five oral papillae on a side, the triangular outermost reaching inside the next papilla, which is angular, wider than long; next squarish, followed by an angular papilla, then a pointed pa- pilla; apical papilla flat and oval. Four equally long teeth, the lowermost broad, cutting edge rounded, uppermost narrow, cutting edge straight. Interbrachial spaces below covered by 2 long genital plates which are separated by irregular scales, outermost largest, and 2 large rounded interbrachial plates. Two small genital slits ^ the disk radius in length. Under arm plates broader than long basally, becoming longer than broad distally, proximal margins convex, distal and lateral margins concave, plates fully in contact. Two wedge-shaped tentacle scales, closely in con- tact, abradial scale slightly larger. There may also be a small accessory scale on the basal arm segments. 42 ALLAN HANCOCK PACIFIC EXPEDITIONS VOL. 8 Color. — Dried specimen, disk and arms above dull dark gray and olive buff irregularly mottled. On the disk scales the color is lighter and more distinct. Interbrachial disk plates have a central, light cream color area encircled with a narrow dark brown band. Entire under surface cream color, general appearance light drab gray. Types.— llo\oX.yY>^, AHF no. 14; 222 paratypes, 11 in M.C.Z. Type locality. — Holotype and 191 paratj^pes, 9 in the Museum of Comparative Zoology, from Station 483-35, 6 fms., Tenacatita Bay, Mexico, February 15, 1935. Thirty-one paratypes as follows: 24, 2 in Museum of Comparative Zoology, from Station 116-33, 2 fms., Cocos Bay, Puerto Culebra, Costa Rica, March 13, 1933; 6 from Station 965- 39, 8-15 fms., Tenacatita Bay, Mexico, May 8, 1939, and one from Station 964-39, 2-8 fms., Tenacatita Bay, Mexico, May 8, 1939. Remarks. — This species is related to O. variegata Liitken and O. crassa Nielsen, differing from both by its depressed disk, broad, short, and markedly tapering arms, the large, rounded interbrachial plates, larger and broader oral shields, and color pattern. These characters are so conspicuous that O. plateia cannot be confused with any known species of the genus. The name selected, plateia^ refers to the unusually depressed disk. 44 ALLAN HANCOCK PACIFIC EXPEDITIONS VOL. 8 PLATE 2 Sigsbeia lae-vis, new species Fig. 1. Upper view Fig. 2. Under view Fig. 3. Side arm view Ophiacantha phragma, new species Fig. 4. Under view Fig. 5. Upper view Fig. 6. Side arm view NO. 2 ZIESENHENNE: NEW OPHIURANS PL. 2 46 ALLAN HANCOCK PACIFIC EXPEDITIONS VOL. 8 PLATE 3 Ophiomyces multispinus, new species Fig. 1. Under view Fig. 2. Upper view Fig. 3. Side arm view Fig. 4. Side view of disk Ophiophraginus ophiacto'tdeSj new species Fig. 5. Under view Fig. 6. Upper view Fig. 7. Side arm view NO. 2 ziesenhenne: newophiurans PL. 3 zmm. 48 ALLAN HANCOCK PACIFIC EXPEDITIONS VOL. 8 PLATE 4 Ophiophragmus papillatus, new species Fig. 1. Under view Fig. 2. Upper view Fig. 3. Side arm view Ophiophragmus lonchophorus, new species Fig. 4. Upper view Fig. 5. Under view Fig. 6. Side arm view Amphichondrius laevis, new species Fig. 7. Under view Fig. 8. Upper view Fig. 9. Side arm view NO. 2 ziesenhenne: newophiurans PL. 4 50 ALLAN HANCOCK PACIFIC EXPEDITIONS VOL. 8 PLATE 5 Amphiodia sculptilis, new species Fig. 1. Under view Fig. 2. Upper view Fig. 3. Side arm view Ophiocnida californica, new species Fig. 4. Upper view Fig. 5. Under view Fig. 6. Side arm view Amphioplus philohelminthius, new species Fig. 7. Under view Fig. 8. Upper view Fig. 9. Side arm view NO. 2 ZIESENHENNE: NEW OPHIURANS PL. 5 52 ALLAN HANCOCK PACIFIC EXPEDITIONS VOL. 8 PLATE 6 Opliionereis didyota, new species Fig. L Under view Fig. 2. Upper view Fig. 3. Side arm view Fig. 4. Side arm view, mid arm Fig. 5. Upper arm view, mid arm Ophiophragmus stellatus, new species Fig. 6. Upper view Fig. 7. Under view Fig. 8. Side arm view Fig. 9. Side view of disk showing marginal disk papillae NO, 2 ZIESENHENNE: NEW OPHIURANS PL. 6 54 ALLAN HANCOCK PACIFIC EXPEDITIONS VOL. 8 PLATE 7 Ophiomisidium leurum, new species Fig. 1. Upper view Fig. 2, Under view Fig. 3. Side arm view Amphiophiura irregularis, new species Fig. 4. Upper view Fig. 5. Under view Fig. 6. Side arm view Ophionereis perplexa, new species Fig. 7. Upper view Fig. 8. Under view Fig. 9. Side arm view NO. 2 ZIESENHENNE: NEW OPHIURANS PL. 7 "^^-^i^/ S''-.^. 56 ALLAN HANCOCK PACIFIC EXPEDITIONS VOL. 8 PLATE 8 Amphiophiura paucisquarna, new species Fig. L Under view Fig. 2. Upper view Fig. 3. Side arm view OphioUpis plateia, new species Fig. 4. Upper view Fig. 5. Under view Fig. 6. Side arm view NO. 2 ZIESENHENNE : NEW OPHIURANS PL. 8 58 ALLAN HANCOCK PACIFIC EXPEDITIONS VOL. 8 PLATE 9 Ophiophragmus disacanthus, new species Fig. 1. Under view Fig. 2. Upper view Fig. 3. Side arm view Ophiodesmus amphilogus, new species Fig. 4. Under view Fig. 5. Upper view Fig. 6. Side arm view NO. 2 ZIESENHENNE : NEW OPHIURANS PL. 9 2 mm. zmm. REPORTS ON THE COLLECTIONS OBTAINED BY ALLAN HANCOCK PACIFIC EXPEDITIONS OF VELERO III OFF THE COAST OF MEXICO, CENTRAL AMERICA, SOUTH AMERICA, AND GALAPAGOS ISLANDS IN 1932, IN 1933, IN 1934, IN 1935, IN 1936, IN 1937, IN 1938, IN 1939, AND IN 1940. THE HOLOTHURIOIDEA COLLECTED BY THE VELERO HI DURING THE YEARS 1932 to 1938 Part I, Dendrochirota (Plates 10-30) By ELISABETH DEICHMANN The University of Southern California Publications Allan Hancock Pacific Expeditions Volume 8, Number 3 Issued June 20, 1941 The University of Southern California Press Los Angeles, California THE HOLOTHURIOIDEA COLLECTED BY THE VELERO HI DURING THE YEARS 1932 to 1938 Part I, Dendrochirota (Plates 10-30) Elisabeth Deichmann Introduction The Panamic region, that is, the stretch of coast which extends from Cerros Island on the western coast of Lower California and southward (including the entire Gulf of California) to Ecuador (with the Galapa- gos Islands) and Peru, forms zoogeographically a natural unit. As far as holothurians are concerned, it has been almost unknown, undoubtedly because the coast in most localities is so exposed that many species live at a greater depth than in other places, as, for example, in the more sheltered bays and coves of the West Indies. The study of the fauna has tempted zoologists for many years, and as early as 1866 Verrill began to compile lists of Echinoderms and Coelen- terates from east and west of Central America. The purpose was chiefly to accumulate data to show the relation of the two faunas to each other. It was Alexander Agassiz's idea that, since so many foi-ms, especially Echinoderms, in the two areas were closely related, one had here a chance to study the effect of separation, or isolation, on the origin of new species, since it was almost certain that the two faunas had once been identical — before the isthmus had been formed. Verrill's lists included 7 species from the Panamic region; of these, 3 are Dendrochirotes. Since then a few more have been described by various workers. The general impression gained was merely that the holothurian fauna was extremely poor and showed some affinities to that of the West Indian seas. It is only recently that the Allan Hancock Expeditions with the Velero III have been able to explode this myth and show that the holothurian fauna actually is as rich as that of the West Indies. During the past six years the Velero III has made extensive collections in the Panamic region and particularly dredgings in that zone hitherto so sadly neglected, between 10-100 fathoms. Almost all the species hitherto described from the region during the last hundred years have been secured and in addition a large number of new species. Thanks to the thorough and methodical way in which [61] 62 ALLAN HANCOCK PACIFIC EXPEDITIONS VOL. 8 the collecting has been undertaken — in most cases under the able leader- ship of Dr. Waldo L. Schmitt, with the enthusiastic support of several young collectors — the material now assembled appears to be so complete that one dares assert that very few additional species are to be expected. Future investigators must be content to secure more material of the species now known or additional information about the distribution of the individual species. The collections consist chiefly of material collected in less than 100 fathoms, or what is usually referred to as shallow water, in contrast to the truly deep sea. The species are distributed among the following four orders — Dendrochirota, Aspidochirota, Molpadonia, and Apoda; the fifth order, Elasipoda, made up exclusively of deepwater forms and a few Arctic species from shallow water, was not met with by the Velero. The Dendrochirota and Aspidochirota have the greatest numbers of repre- sentatives. The material of the former order has proved to be the most interesting, because it includes a large number of new species which are restricted to the Panamic region or have close relatives in the West Indies, while the representatives of the Aspidochirota are mostly widespread species. The Molpadonia and Apoda have so few representatives that it is difficult to make any general statements about their relations to other faunas. In the following account all the Dendrochirota hitherto known from the Panamic region are monographically treated. Besides the material secured by the Velero III, a few undescribed specimens from the M.C.Z. have been included to make the work complete. Much use has also been made of Selenka's old types and other material from the Panamic region which I have had occasion to examine at various times. Special attention has been paid to comparison with the holothurians from adjacent waters, that is, the West Indian, Californian, Chilean, and Hawaiian seas. As far as the Dendrochi rotes are concerned, one may say that the affinities are definitely with the West Indian fauna, while a few forms have related representatives in Californian waters. Several species are also known from the Chilean coast, but relationship to the Hawaiian fauna seems to be nil. More extensive explorations may, however, show that a somewhat richer Dendrochirote fauna exists in Hawaii than has hitherto been sup- posed. It is a great pleasure to thank the Allan Hancock Foundation for the privilege of studying this valuable collection, thus enabling me to realize my long-felt desire to write a monograph on the holothurians of the NO. 3 deichmann: holothurioidea; parti, dendrochirota 63 Panamic region. Particularly do I wish to thank Dr. Irene McCulloch for her unflagging interest in this paper and for the amount of her own valuable time which she unstintingly has given whenever I worked in Los Angeles. Composition of the Fauna From the Panamic region 15 species of Dendrochirota, valid and dubious, were described up to 1936; during the following years 6 new species were added, thus bringing the total number up to 21. The present monograph treats 43 species which are valid and 3 which are so poorly described that they must be completely rejected, unless the types should be rediscovered. Three of the 43 valid species are probably extraterritorial — Pachythyone rubra (H. L. Clark) and Thyonepsolus nutriens H. L. Clark, not known with certainty south of Santa Cruz Island, southern California, and Psolus patagonicus Ekman from the Cape Horn region. All the valid species have been examined ; of these, 34 are represented in the Allan Hancock Foundation collections, while the remaining 9 have been studied in the M.C.Z. and in the U.S.N.M. ; in five cases the types have been available. Of the 34 species in the Hancock collections 16 are new, while the 17th new species came from the collec- tions of the Stranger^ which are deposited in the M.C.Z. List of Dendrochirota from the Panamic Region, Including a Few from the Adjacent Northern and Southern WATERsf Cucumaria californica Semper p. 79 Leptopentacta nina, new species p. 97 Cucumaria chilensis Ludwig p. 80 Pentacta peruana (Semper) p. 99 Cucumaria dubiosa Semper p. 81 Thyonacta mexicana, new species p. 101 Cucumaria crax, new species p. 83 Thyone neofusus, new species p. 104 Cucumaria godeffroyi Semper (0)* p. 83 Thyone bidentata, new species p. 105 Pentamera zacae Deichmann (0) p. 85 Thyone parafusus, new species p. 106 Pentamera beebei Deichmann (0) p. 86 Thyone strangeri, new species p. 107 Pentamera chierchia (Ludwig) p. 86 Neothyone gibber (Seienka) p. 109 Pentamera chiloensis (Ludwig) p. 88 Neothyone panamensis (Ludwig) p. 112 Pentamera panamensis Verrill (0)* p. 89 Neothyone gibbosa, new species p. 113 Neopentamera anexigua, new genus, Pachythyone rubra (ILL. Clark) (0) p. 115 new species p. 90 Pachythyone lugubris (Deichmann) p. 116 Apentaraera lepra, new genus, new Pachythyone pseudolugubris, new species p. 92 species p. 116 Leptopentacta nova, new species p. 95 Athyone glasselli (Deichmann) (0) p. 119 Leptopentacta panaraica, new species p. 96 Anaperus peruviana (Lesson) (0)* p. 120 t Dubious species are marked with an *; those not secured by the Allan Hancock Expeditions are marked with (0). 64 ALLAN HANCOCK PACIFIC EXPEDITIONS VOL. 8 Euthyonidium ovulum (Selenka) p. 124 Thyonepsolus hancocki, new species p. 140 Euthyonidium veleronis, new species p. 126 Psolidium dorsipes Ludwig p. 143 Athyonidium chilensis (Semper) p. 127 Psolidium eubuiiatum, new species p. 144 Pattalus mollis Selenka p. 130 Psolidium ekmani, new species p. 145 Phyllophorus aculeatus Ludwig (0) p. 133 Psolidium planum, new species p. 145 Phyllophorus zacae Deichmann p. 134 Psolus squaraatus (Keren), var. Thyonepsolus nutriens H. L. Clark p. 138 segregatus Perrier (0) p. 147 Thyonepsolus beebei Deichmann p. 139 Psolus patagonicus Ekman (0) p. 148 Thyonepsolus veleronis, new species p. 140 Psolus diomedeae Ludwig p. 149 List of Stations at which Dendrochirote Holothurians Were Collected 11-32 (?). January 12, 1932. Conway Bay, Indefatigable Island, shore, Galapagos. Thyonepsolus nutriens H. L. Clark (Possibly some error in the station number.) 73-33. February 13, 1933. Albemarle Island, Cartago Bay, shore, Galapagos. Pentamera chierchia (Ludwig) 80-33. February 15, 1933. Duncan Island, Smitty's Shore, collecting. In coral. Pentamera chierchia (Ludwig) 132-34. January 4, 1934. Braithwaite Bay, Socorro Island, Mex., 40 fms. Pentamera chierchia (Ludwig) Neothyone gibber (Selenka) 143-34. January 11, 1934. Wenman Island, Galapagos, 100-150 fms. Psolus diomedeae Ludwig 145-34. January 12, 1934. North end of Albemarle Island, Galapa- gos, 6-7 fms. Pachythyone pseudolugubris, new species 147-34. January 13, 1934. South of Tagus Cove, Albemarle Island, Galapagos, 30 fms. Thyonepsolus veleronis, new species 166-34. January 19, 1934. Charles Island, Galapagos; shore collect- ing on Black Beach. Neothyone gibbosa, new species 189-34. January 25, 1934. Cartago Bay, Albemarle Island, Galapagos; shore, among Porites. Pentamera chierchia (Ludwig) NO. 3 DEICHMANN : HOLOTHURIOIDEA ; PART I, DENDROCHIROTA 65 190-34. January 26, 1934. Lat. 0°55'S., Long. 90°30'W., 58-60 fms. Sand. Pentamera chiloensis (Ludwig) Thyone neofusus, new species Phyllophorus zacae Deichmann 209-34. February 9, 1934. North of Point Sta. Elena, La Libertad, Ecuador, 8-10 fms. Pentamera chiloensis (Ludwig) 212-34. February 10, 1934. La Plata Island, Ecuador, dredging, 45-55 fms. Sand, shale, rock, mud. Psolidium eubullatum, new species 213-34. February 10, 1934. La Plata Island, Ecuador, 7-10 fms. Pentamera chiloensis (Ludwig) Thyonepsoliis hancocki, new species Psolidium eubullatum, new species Psolidium ekmani, new species Psolus diomedeae Ludwig 244-34. February 21, 1934. Bahia Honda, Panama, dredging between Medidor and Pacora islands, 30-35 fms. Thyonacta mexicana, new species 245-34. February 21, 1934. Bahia Honda, Panama, dredging off north- west point of Pacora Island, 15-25 fms. Thyone bidentata, new species 249-34. Februaiy 22, 1934. Bahia Honda, Panama, dredging in 15-20 fms. Outside of island, south of bay. Rock. Thyone bidentata, new species 251-34. February 22, 1934. Secas Islands, Panama, dredging south and west of group in 15 fms. Rock. Thyone bidentata, new species 259-34. Februaiy 28, 1934. Tangola Tangola, Mex., 15-20 fms. Leptopentacta panamica, new species 261-34. March 1, 1934. Tangola Tangola, Max., 15-20 fms. In coral. Cucumaria calif ornica Semper Euthyonidium ovulum (Selenka) Thyonepsolus beebei Deichmann 66 ALLAN HANCOCK PACIFIC EXPEDITIONS VOL. 8 264-34. March 2, 1934. South and west of White Friar Island, Petat- lan Ba3% Mex., 25 fms. Pachythyone pseudolugubris, new species Pentacta peruana (Semper) 272-34. March 4, 1934. Tenacatita Bay, Mex., dredging in 25 fms., between white rocks and bay. Coarse sand. Thy one parafusiis, new species 275-34. March 4, 1934. Off Navidad Head, Tenacatita Bay, Mex., 25-35 fms. Leptopentacta panamica, new species Thyone bidentata, new species Thy one parafusus, new species 281-34. March 7, 1934. West coast of L. Calif., Santa Maria Bay, 35-40 fms., 1 mile west of Hughes Point. Leptopentacta nova, new species 283-34. March 9, 1934. Off Thurloe Point, Thurloe Bay, west coast of L. Calif., 8-10 fms. Cucmnaria crax, new species Pachythyone lugubris (Deichmann) Thyonepsolus beebei Deichmann 286-34. March 9, 1934. Thurloe Point, west coast of L. Calif. Shore collecting. Cucumaria californica Semper 287-34. March 10, 1934. Cerros Island, west coast of L. Calif., 10-15 fms. (close to kelp beds). Pachythyone lugubris (Deichmann) 315-35. December 8, 1934. Indefatigable Island, opposite Gordon Rocks. In corals. Pentamera chierchia (Ludwig) 365-35. January 10, 1935. Off southeast corner of Lorenzo Island, Cal- lao, Peru, 10 fms. Cucumaria dubiosa Semper 366-35. January 10, 1935. Between rocks south of Lorenzo Island, Callao, Peru. Cucumaria dubiosa Semper 375-35. January 13, 1935. Independencia Bay, Peru, shore. Pattalus mollis Selenka 384-35. January 14, 1935. Independencia Bay, Peru, 5 fms., % mile off shore, east side of bay. Cucumaria dubiosa Semper NO. 3 deichmann: holothurioidea; part i, dendrochirota 67 391-35. January 17, 1935. Lobos de Afuera, Peru, shore of main island with lighthouse, rocks. Neothyone gibber (Selenka) Neothyone gibbosa, new species Pattalus mollis Selenka 401-35. January 19, 1935. Manta, Ecuador, 1 fm., below first rocky point. Pentamera chierchia (Ludwig) 423-35. January 25, 1935. Port Utria, Colombia, 20 fms., close to shore. Leptopentacta panamica, new species Thyone bidentata, new species 429-35. January 27, 1935. Octavia Bay, Colombia, 30-35 fms., north end of channel. Coarse sand and gravel. P solus diomedeae Ludwig 431-35. January 27, 1935. Octavia Bay, Colombia, 45 fms., north of Octavia Strait, south end of channel. Psolus diomedeae Ludwig 464-35. Februar)' 8, 1935. Playa Blanca, Costa Rica, 2 fms., in coral, south shore of bay. Pentamera chierchia (Ludwig) 465-35. February 8, 1935. Plaj^a Blanca, Costa Rica, shale between beach and rocky reef. Euthyonidium veleronisj new species Neothyone gibbosa, new species 466-35. February 9, 1935. Parker Bay, Costa Rica, shore of small is- land at north side of bay. Cucumaria calif ornica Semper Cucumaria dubiosa Semper Neothyone gibber Selenka 467-35. February 9, 1935. Parker Bay, Costa Rica, 2 fms. Rock and algae. Pentamera chierchia (Ludwig) 473-35. February 9, 1935. Parker Bay, Costa Rica, 2 fms., in coral. Pentamera chierchia (Ludwig) Neothyone gibber (Selenka) 517-36. February 25, 1936. East side of San Francisco Island, Gulf of Calif., 15 fms. Phyllophorus zacae Deichmann 68 ALLAN HANCOCK PACIFIC EXPEDITIONS VOL. 8 521-36. February 27, 1936. Agua Verde Bay, Gulf of Calif., 5-10 fms. Thyonepsolus hancocki, new species 527-36. February 28, 1936. South of Mangles Anchorage, Gulf of Calif., shore. Cucumaria calif ornica Semper 529-36. March 1, 1936. Off San Francisquito Bay, Gulf of Calif., 165 fms. Thyonepsolus hancocki, new species Psolus diomedeae Ludwig 537-36. March 2, 1936. Spit, north of mill site, Angeles Bay, Gulf of Calif., shore. Cucumaria calif ornica Semper 540-36. March 3, 1936. Puerto Refugio, Angel de la Guardia Island, Gulf of Calif., shore. Neothyone panamensis (Ludwig) 545-36. March 4, 1936. Puerto Refugio, Angel de la Guardia Island, Gulf of Calif., west of rock spit at river wash, shore. Neothyone gihbosa, new species 554-36. March 8, 1936. Parallel to Angel de la Guardia Island, Gulf of Calif., east side, 10 fms. Thyonacta mexicana, new species 557-36. March 8, 1936. Off White Rock, Isla Partida, Gulf of Calif., 45 fms. Apentamera lepra, new species 562-36. March 10, 1936. North of San Esteban Island, Gulf of Calif., 20-70 fms. Thyonacta mexicana, new species 591-36. March 16, 1936. Port Escondido, shore, L. Calif., rock. Neothyone gihbosa, new species Euthyonidium ovulum (Selenka) 596-36. March 16, 1936. Port Escondido, Gulf of Calif., 20 fms. Pentamera chierchia (Ludwig) 617-37. March 2, 1937. San Juanico Bay, southern end of L. Calif., 24 fms. Cucumaria californica Semper 623-37. March 4, 1937. Cabeza Ballena, east of Cape San Lucas, L. Calif., shore. Cucumaria californica Semper NO. 3 deichmann: holothurioidea; parti, dendrochirota 69 633-37. March 6, 1937. San Gabriel Bay, Espiritu Santo Island, Gulf of Calif., 18 fms. Thyonacta niexicana, new species 677-37. March 15, 1937. Ildefonso Island, Gulf of Calif., 50 fms. Fentamera chiloensis (Ludwig) 679-37. March 15, 1937. Outside of Concepcion Bay, Gulf of Calif., 30 fms. Thyone bidentata, new species 683-37. March 15, 1937. Outside of Concepcion Bay, Gulf of Calif., 12 fms. Cucumaria californica Semper Pentamera chierchia (Ludwig) Neopentamera anexigua, new species Thyone bidentata, new species Pachythyone pseudolugubris, new species 686-37. March 16, 1937. Concepcion Bay, L. Calif., 12 fms. Thyone bidentata, new species 699-37. March 19, 1937, Angeles Channel, Gulf of Calif., 30 fms. Cucumaria chilensis Ludwig 719-37. March 24, 1937. Consag Rock, Gulf of Calif., 6-8 fms. Thyonacta mexicana, new species 744-37. April 1, 1937. Near Point Piaxtla, Sinaloa, Gulf of Calif., 6-8 fms. Pachythyone pseudolugubris, new species Psolidium dorsipes Ludwig 780-38. January 14, 1938. Chatham Bay, Cocos Island, Costa Rica, 40-47 fms. Psolus diomedeae Ludwig 784-38. January 17, 1938. Darwin Bay, Tower Island, Galapagos, Middle Beach, shore. Pentamera chierchia (Ludwig) 792-38. January 20, 1938. Off Daphne Minor Island, Galapagos, 70- 80 fms. Psolus diomedeae Ludwig 814-38. January 28, 1938. North of Hood Island, Galapagos, 20-40 fms. Thyone neofusus, new species 70 ALLAN HANCOCK PACIFIC EXPEDITIONS VOL. 8 816-38. January 29, 1938. North of Hood Island, Galapagos, 50-100 fms. Phyllophorus zacae Deichmann 820-38. February 6, 1938. San Nicholas Bay, Peru, 10-25 fms. Pattalus mollis Selenka 824-38. February 7, 1938. San Juan Bay, Peru, 15-20 fms. Cucutnaria calif ornica Semper (poor specimen) 828-38. February 8, 1938. San Juan Bay, Peru, shore. Athyonidium chilensis (Semper) Pattalus mollis Selenka 831-38. February 9, 1938. Independencia Bay, Peru, east side of bay, shore. Athyonidium chilensis (Semper) 833-28. February 10, 1938. Independencia Bay, Peru, off north en- trance, 8 fms. Pentamera chiloensis (Ludwig) 837-38. February 11, 1938. North Chincha Island, Peru, shore. Pattalus mollis Selenka 844-38. February 14, 1938. Lobos de Afuera Island, Peru, shore. Neothyone gibber (Selenka) Neothyone panamensis (Ludwig) Neothyone gibbosa, new species Euthyonidium ovulum (Selenka) Pattalus mollis Selenka 845-38. February 15, 1938. Sechura Bay, Peru, 9.5 fms. Psolidium planum, new species 850-38. February 23, 1938. Cape San Francisco, Ecuador, 15 fms. Leptopentacta nina, new species 854-38. February 24, 1938. Gorgona Island, Colombia, north of island, mud, rocks, 40-60 fms. Thyonepsolus hancocki, new species Psolidium planum, new species Psolus diomedeae Ludwig 863-38. March 1, 1938. Bahia Honda, Panama, off North Island, 30-50 fms. Apentamera lepra, new species Psolidium dorsipes Ludwig Psolidium ekmani, new species NO. 3 deichmann: holothurioidea; part i, dendrochirota 71 Order DENDROCHIROTA Diagnosis. — Plankton feeding holothurians with dendritic tentacles, rarely fingerlike; number var>'ing from 10, the 2 ventral often smaller, in some cases less than 10, or 12-20, up to 30 in a few genera. Feet ar- ranged along the ambulacra or also scattered in the interambulacra ; ter- minal and dorsal ones often modified into papillae. Internally a calcareous ring, simple, or complex, with shorter or longer posterior prolongations. One or more stone canals, one or more Polian vesicles; usually a well-developed muscle stomach; intestine with the 3 loops attached by mesenteries ; that of the third loop may run along the right or the left side of the midventral muscle band. Retractor muscles well developed, distinctly separated from the longitudinal muscles. Re- spiratory trees mostly well developed, usually attached to the lateral inter- ambulacra. Gonads forming 2 tufts with a shorter or longer genital stolon, and shorter or longer tubes, usually divided near the base. Spicules tables, cups, buttons, or plates, et cetera, in some cases large scales covering the entire body, or the dorsal side and the ends. Feet with large end plate, or a vestige, or end plate completely reduced. Tentacles with larger or smaller plates or rods, often rosettes, or no spicules at all. In many forms the spicules disappear normally with advancing age, partly or completely. Remarks. — The order seems to be comparatively young. The members occur with few exceptions in shallow water and the distribution of the individual species is rather restricted aside from the deepwater forms and certain Arctic and Antarctic forms. Key to the Families of Dendrochirota 1. Part of the ventral side developed as a thin-walled creeping sole. III. Psolidae p. 135 1. No part of the ventral side developed as a thin- walled creeping sole. II. 2. Tentacles 10 in number or less I. Cucumariidae p. 76 2. Tentacles more than 10 in number (12-20, 30). II. Phyllophoridae p. 122 Remarks. — The old division of dekachirote and polychirote forms, designating those with 10 tentacles (or less) and those with more than 10, has been abandoned, as it is completely artificial. 72 allan hancock pacific expeditions vol. 8 Characters Used for Identification Macroscopical characters Size. — Where full-grown specimens are available, size constitutes a fairly good character, although some caution must be used, as many species are able to contract their bodies to an unbelievable degree, while others rarely change much. Most Den drochi rotes are small forms, that is, less than 10 cm. long, a number measure between 10-15 cm., and few are large, above 20 cm. The largest forms are known to reach a length of 50 cm. when fully expanded. The chief difficulty about using size for identification is that one so often encounters young individuals. Speci- mens 1 cm. long are usually difficult to identify; the feet are frequently not distributed in their tj^pical pattern, and the spicules may be very different from what they are in more mature individuals. Where very young specimens are involved, the characters, "feet ambulacral" or "feet interambulacral," cannot be used, as all the forms with interambulacral feet begin with feet in the ambulacra only. In some species the inter- ambulacral feet begin to appear when the animal is less than 1 cm. long, but in others they appear much later, when the animal is 2-3 cm. long. For that matter, veiy little is known about the growth rate of the Dendrochi rotes or any order of seacucumbers. Mitsukuri found that the Japanese Aspidochirote form Stichopus japonicus reaches the unbelievable length of 25 cm. in a little over a year, but such a rapid growth is prob- ably an exception, and under no circumstances can it be assumed to be the normal in the Dendrochirotes without definite proof. Smaller species may probably reach their full length in one or two years; larger forms, as, for example, Thyone briareus (Lesueur), require undoubtedly four to five years to reach their full size. Tentacles. — The full number is quickly reached in the "dekachirote" forms. In the "polychirote" forms (those which have tentacles arranged in 2 well-defined circles and definitely of two sizes) seem to develop the full number before they have reached the length of about 1 cm., while in the species which have the 2 circles indistinctly set off and with ten- tacles of varying size the full number seems to be reached rather late. In many "dekachirote" forms the two ventral tentacles are much smaller than the others, and the difference in size is retained throughout the animal's life. In a few species the number of tentacles falls below ten in various deep sea forms and in that case the tentacles are often unbranched. Tube feet. — ^The arrangement of the tube feet is of importance in reasonably mature individuals and constant for the different species. The NO. 3 deichmann: holothurioidea; parti, dendrochirota 73 number of feet increases with advancing age. Man}^ descriptions, "feet in 3-4 rows," "single row, etc.," are of little value except when the ani- mal is well expanded and its size also is given. In some species the feet are heavily armed with spicules and unable to retract; in others equally well armed they may be withdrawn. Where the feet contain few spicules, the feet are often completely retractile. In younger individuals the ar- rangement of the feet is often untypical, as mentioned above. Inner organs. — Much space has usually been devoted to the inner anatomy of the Dendrochi rotes, but with the exception of the calcareous ring, the stone canal, Polian vesicle, and gonads, all other organs may usually be ignored. A few species are said to lack a muscle stomach, but I am not sure that the observation is correct. The course of the intestine and the attachments of the mesenteries to the body wall are fairly stable characters, although some variation has been noted, but the contracted, contorted condition wherein the material often is preserved, or the com- plete loss of inner organs, makes it impossible to use these structures consistently. The Cucumariidae seem typically to have the third mesen- tery attached on the right side of the midventral muscle band, the Phyl- lophoridae seem to have it attached to the left, and the Psolidae have it either way. The thickness or thinness of the longitudinal muscles, the place of attachment for the retractors, the shape of the branches of the respiratorj'^ trees, et cetera, are all characters of rather dubious value and the use of them has often caused misidentification. Calcareous ring. — The calcareous ring presents a character of utmost importance, as certain types invariably seem to be combined with a cer- tain arrangement of the tube feet and certain types of spicules. The calcareous ring is designated as simple when the radials and interradials have fairly low, broad basal portions with shorter or longer anteriorly projecting teeth, while the posterior margin may be almost straight or undulated, sometimes with faint protuberances on the radials. In the complex ring the radials have distinct posterior prolongations, the so-called "tails"; and the body of the radials may be deeply cleft, some- times almost to the base of the anterior tooth. In some species the tails may be secondarily more or less resorbed or hidden in the tissue and hence less noticeable. The interradials either are fairly broad, overlapping the ra- dials as heart-shaped or diamond-shaped pieces, or are narrow, often quite tall, rectangular, and firmly united with the radials; rarely are they vestigial ; the anterior tooth may be short or long. The complex cal- careous ring may furthermore be composed of several smaller pieces as a 74 ALLAN HANCOCK PACIFIC EXPEDITIONS VOL. 8 mosaic, but this "polyplacous" condition is perhaps not always an entirely reliable character, as in certain species some specimens have polyplacous rings, while in others the condition is little or not at all pronounced — observed in Pentarncra calcigera (Stimpson). Stone canal and Polian vesicle. — In most Dendrochirota there is a single dorsal stone canal with round or oblong head, attached to the dor- sal mesentery, or free, and one or two ventral Polian vesicles. In a few species, particularly among the "polychirote" forms, there are several free stone canals and often a large number of Polian vesicles also. In some species the Polian vesicles have been found to be branching, but in most cases they are simple. Gonads. — Only few and scattered observations have been made on the gonads in the holothurians and here also too much emphasis has been laid on the size of these organs in different animals. In Stichopus japoni- cus Mitsukuri observed that the sexually mature individuals, about 3 years old, in short time developed few long tubes of eggs and sperms, which were shed, and the tubes shriveled up and new ones developed in the following year. This condition is probably the typical one in the aspidochirote forms. In the larger Dendrochirota it seems as if the gonad tubes increase in size over a period of years. It is possible that some eggs or sperms are developed before the full size of the tubes is reached. In Thyone brtareus (Lesueur) it has been observed (Kille, 1939) that the number of tubes increases slightly with advancing age. The increase takes place in the anterior part of the gonads, while a few shriveled-up tubes are found posteriorly. A similar observation has been made on Athyonid- ium chilensis (Semper). Very likely smaller, immature tubes will be found to be present in most Dendrochirotes, which continue their growth for several years. It is also possible that some of the so-called "hermaphro- ditic gonads" merely represent the mature and immature portions of a unisexual gonad. In the larger species the number of tubes is large, more than 100 in each tuft; in the smaller and supposedly more short-lived forms the number of tubes in each tuft is low, varying between 5-20 or thereabout, and no immature portion seems to be present. More observa- tions are, however, needed before any definite statements can be made. Microscopical characters The spicules in the integument, feet, introvert, and tentacles form valuable characters for identification of Dendrochirota as well as most other holothurians. Certain types of spicules or derivates of these occur, usually together, and accompany certain anatomical features. The spicules NO. 3 DEICHMANN : HOLOTHURIOIDEA ; PART I, DENDROCHIROTA 75 change considcrabh^ during the animal's life, either becoming more com- plex or degenerating; in some cases they disintegrate almost completely, with the exception of the end plate which normally seems to persist in the species where it is well developed from the beginning; when it is rudimentary in the young individual, it quickly becomes resorbcd. In the integument two layers of spicules are typically present, an ex- ternal, the function of which is presumably to give roughness to the skin, and an inner layer, which gives stiffness. The spicules in the outer layer seem definitely fixed in their position, usually with the external side rough with spines, often perforating the skin, while the spicules in the inner layer are able to slide over each other when the animal contracts — as the cards in a deck — and these spicules are therefore more smooth and flat. Either layer or both may be reduced or lacking; the inner layer is never present in very young individuals, while the outer layer frequently is lost or reduced with age. Usually the spicules in the 2 layers are ex- tremely different, in other cases they are less sharply difiFerentiated. Com- mon tj^pes in the external layer are : the table, a basal plate with a num- ber of pillars (1-6) ending in a varying number of teeth, or the basket (or cup) — a hollow body usually with a number of spines developed on the edge. Other types are oval buttons and plates, often with spines or a rough reticulated mass on the external side. The inner layer consists of regular or irregular buttons or plates, smooth or knobbed. Sometimes also large and more complex bodies may be found. A few forms have the body covered partly or completely by scales. In that case the external layer of spicules is usually quite insignificant, although it may contain rather interesting types of deposits. In the tube feet a large end plate is almost invariably present in the species which have well-developed tails on the calcareous ring. Likewise, a well-developed end plate is usually accompanied by supporting tables with a curved disk and a spire of varying development — sometimes the spire is totally absent except in very young individuals, but it is usually possible to ascertain whether a supporting rod is derived from the table type or not. In more papilliform appendages the end plate is usually small or lacking. No end plate, or a vestigial end plate is usually combined with a simple calcareous ring, and the supporting rods are either simple or pro- vided with a third arm, more or less platelike, often irregularly star shaped. iti^/r / 76 ALLAN HANCOCK PACIFIC EXPEDITIONS VOL. 8 The introvert (the thin-vvalled skin between the base of the tenta- cles and the anteriormost tube feet) often contains characteristic spicules. In the species where the spicules are reduced gradually they are fre- quently retained here. They usually resemble those found in the external layer of the skin but are often more delicate and more complex. The tentacles may be filled with large perforated plates or rods, or contain minute rods or delicate plates, rarely a mixture of both. Rosettes seem typical of certain species; they are apparently restricted to tropical and subtropical forms and occur often in both the introvert and the tentacles. In many cases the spicules in the tentacles become completely reduced with advancing age. Family I. Gucumariidae Key to the Genera of Gucumariidae Known from the Panamic Region 1. Body more or less globose, covered by large, reticulated scales. Deepwater forms Sphaerothuria Ludwig 1. Body not globose, not covered by large, reticulated scales. . 2 2. Spicules spinous crosses. Deepwater forms Staurocucumaria Ekman 2. Spicules not spinous crosses 3 3. Feet restricted to ambulacra 4 3. Feet also found in the interambulacra 7 4. Feet retractile, soft, with end plate reduced or lacking. Spicules plates or buttons, often reduced 1. Cucumaria Blainville (partim) p. 77 4. Feet not retractile 5 5. Skin covered by huge reticulated plates and smaller spicules. Calcareous ring at most with short posterior prolongations. 5. Leptopentacta H. L. Clark p. 92 5. Skin not covered by huge reticulated bodies. Calcareous ring with long posterior prolongations 6 6. Spicules 2-pillared tables, spire sometimes reduced. Feet with large end plate. Spicules rarely reduced. 2. Pentamcra Ayres p. 84 6. Spicules knobbed buttons, or irregular. Feet with large end plate 3. Neopentamera, new genus p. 90 7. Feet occur in interambulacra but chiefly in the dorsal ones. 8 NO. 3 deichmann: holothurioidea; parti, dendrochirota 77 7. Feet occur in interambulacra but chiefly in the ventral ones. (Thyones. 1.) 9 8. Dorsal feet normally developed, soft, retractile. Spicules plates or buttons, often reduced. 1. Cuciunnria Blainville (pnrihn) p. 77 8. Dorsal feet mostly papilliform. Spicules few or numerous. . 10 9. Dorsal interradial feet few, small, easily overlooked ; radial feet numerous. Resembles Pentamera. 4. A pentamera, new genus p. 91 9. Dorsal feet partly large, wartlike or papilliform. Spicules crowded 6. Pentacta Gold fuss p. 96 10. Spicules numerous, forming a crowded layer 11 10. Spicules more or less reduced, scattered, or lacking 14 11. Spicules as 2- or 4-pillared tables. Calcareous ring with long posterior prolongations 8. Thy one Oken p. 102 11. Spicules as knobbed buttons 12 12. Feet at first comparatively few, in distinct rows along the am- bulacra, later crowded in the interambulacra, mostly papilli- form 7. Thyonacta, new genus p. 101 12. Feet numerous, but in almost indistinct rows along the am- bulacra 13 13. No external plates covei'ed by reticulum. Either baskets or buttons with spinous handle. . 9. Neothyone, new genus p. 108 13. External plates covered by a reticulum 10. Pachythyone, new genus p. 114 14. Spicules swollen buttons, often obviously derived from tables. Calcareous ring with long, well-developed posterior prolonga- tions 11. AthyonCj new genus p. 118 14. Spicules apparently lacking except the end plate in the feet. Calcareous ring with short posterior prolongations sometimes reduced 12. Anaperus Troschel p. 120 Genus 1. CUCUMARIA Blainville Diagnosis. — Dendrochirotes with 10 tentacles, of equal size or the ventral ones smaller. Feet large, soft, in 5 bands, in some forms also scat- tered in the interradii, particularly dorsally. Calcareous ring low, simple. 78 ALLAN HANCOCK PACIFIC EXPEDITIONS VOL. 8 Spicules plates or buttons, knobbed or smooth, often reduced. Feet with a vestige of an end plate or none at all ; walls supported by rods, often 3 armed, or plates. Introvert and tentacles with perforated plates and rods. The spicules show tendency to become reduced in many forms. Type species. — Cucumaria frondosa (Gunnerus). Remarks. — The diagnosis embraces only the members of the genus Cucumaria sensu strictiore. The well-known type species is the only rep- resentative of the genus in the northern Atlantic, while the northern Pacific, including Bering Sea, harbors 3 large species : C. japonicn Semper, C. fallax Ludwig, and C. miniata Brandt. From the west coast of North America a number of smaller forms have been described : C. vegae Theel, C. lubrica H. L. Clark, C. curata Cowles, C. pseudocurata Deichmann. From the Panamic and Peruvian-Chilean region 4 species are reported with certainty, while a fifth species, from Chile, imperfectly described, is briefly discussed below. Key to the Species of Cucumaria s. str. Known from the Panamic Region 1. Spicules small, crackerlike buttons or plates with marginal holes or incisions. ... 4. Cucumaria crax, new species 1. Spicules larger plates and buttons, knobbed to smooth, often reduced in older individuals 2 2. Feet not restricted to the ambulacra, fairly numerous in the dorsal interambulacra. . . 3. Cucumaria duhiosa Semper 2. Feet restricted to the ambulacra 3 3. Tentacles soft, bushy, of equal size. Spicules usually almost lacking in larger individuals (6-10 cm. long), in young indi- viduals as knobbed oblong plates, often with a dentate handle ; supporting rods in feet predominantly 3-armed rods. . . . 1. Cucumaria calif ornica Semper 3. Tentacles rigid with spicules, not bushy, ventral ones small. Spicules strongly knobbed circular plates or smooth ones, usu- ally without a spinous handle. Feet with narrow, bandlike sup- porting rods 2. Cucumaria chilensis Ludwig Remarks. — Not included in the key is Cucumaria godeffroyi Semper, which possibly is a strictly southern form. See p. 83. NO. 3 DEICHMANN : HOLOTHURIOIDEA ; PART I, DENDROCHIROTA 79 1. Cucumaria calif omica Semper Plate 10, Figs. 6-8 Cucumaria calif ornica Semper, 1868, p. 235, pi. 39, fig. 16; pi. 40, fig. 10.— Lampert, 1885, p. 147.— Theel, 1886, p. 109; 1886a, p. 8. Nee Cucumaria calif ornica Edwards, 1910, p. 601 (i.e., C. fallax Lud- wig — an Arctic species, known from Bering Sea). Diagnosis. — Medium-sized form (10 cm.), with soft, bushy tentacles of equal size. Skin soft, slipper\'; feet large, soft, completely retractile, restricted to the ambulacra. Calcareous ring simple, other anatomical features very nearly as in the type species. Spicules oblong knobbed plates, often with a spinous handle, and 4-holed buttons, frequently reduced or lacking. Feet with a vestige of an end plate and numerous 3-armed per- forated supporting rods. Introvert and tentacles with perforated plates or rods, often completely reduced. Color varying from dark slate gray or black to almost white ; tentacles seem always to be darkly pigmented. Holotype. — Possibly in Germany. Type locality. — Mazatlan, Mexico. Distribution. — ^West coast of Mexico and Central America, possibly to Peru. Depth. — From shore to about 100 fms. Specimens examined. — Numerous in the U.S.N.M., and the follow- ing from the Allan Hancock Expeditions : 261-34. Tangola Tangola, Mex., 15-20 fms., March 1, 1934, 4 speci- mens. 286-34. Thurloe Bay, Thurloe Point, L. Calif., Mex., shore, March 9, 1934, 8 specimens. 466-35. Parker Bay, Costa Rica, shore, February 9, 1935, 3 specimens. 527-36. South of Mangles Anchorage, L. Calif., Mex., shore, Feb- ruary 28, 1936, 1 specimen. 537-36. Spit, north of mill site, Angeles Bay, L. Calif., Mex., shore, March 2, 1936, 10 specimens. 617-37. San Juanico Bay, L. Calif., Mex., 24 fms., March 2, 1937, 2 specimens. 623-37. Cabeza Ballena, east of Cape San Lucas, shore, March 4, 1937, 2 specimens. 683-37. Concepcion Bay, L. Calif., Mex., 12 fms., March 15, 1937, 1 specimen. 824-38. San Juan Bay, Peru, 15-20 fms., February 7, 1938, 1 specimen. 80 ALLAN HANCOCK PACIFIC EXPEDITIONS VOL. 8 Remarks. — The species seems to be common in the Gulf of Cali- fornia and along the west coast of Mexico and Central America. A single record exists from Peru, possibly an error in labeling. Its soft skin, bushy tentacles, and usually dark coloration make it easy to recognize. In life it is often bright red ; in alcohol it fades to white with dark tentacles. The name calif ornica has unfortunately been applied to the common frondosa-Wke form from Bering Sea, C. fallax Ludwig. During the Albatross expeditions a single specimen of this Arctic form evidently got mixed up with some material from the Galapagos Islands ; Edwards, who worked over the material, gave the name calif ornica to this specimen with the dubious locality, as well as to the larger individuals of C. fallax from Bering Sea (while the smaller individuals were identified as C. fallax). The supposedly Galapagos specimen, which shows strong signs of having been dried up, is a typical huge, brownish, frondosa-like form and cannot be separated from the individuals of C. fallax of the same size collected in the Bering Sea.^ Cuctimaria californica, on the other hand, is much smaller and either completely slate gray or black, or the tentacles and part of the anterior end are dark colored. Its spicules are entirely different from those found in C. fallax. 2. Gucumaria chilensis Ludwig Plate 11, Figs. 3-5 Cucumaria chilensis Ludwig, 1875, pi. 6, fig. 11 (used only in the plate explanation). Cucumaria exigua (partim) Ludwig, 1874, p. 84. — Lampert, 1885, p. 145.— Theel, 1886, p. 108. Diagnosis. — Medium-sized form. Feet restricted to ambulacra, re- tractile. Tentacles not bushy, filled with spicules, the 2 ventral ones small. Calcareous ring simple; other anatomical features apparently typical of the genus. Spicules 4-holed buttons and smooth to knobbed plates. Feet with rudimentary end plate and numerous slender supporting rods, slightly shorter in the dorsal appendages. Introvert and tentacles with large per- forated plates and rods. Color yellow, with or without irregular spots, or mottled gray and brown. Holotype. — Hamburg Museum. Type locality. — Chile. Distribution. — Various localities in Chile. 1 Material in U.S.N.M. NO. 3 deichmann: holothurioidea ; part i, dendrochirota 81 Depth. — Not recorded for the type and paratypes. Specimens examined. — A single specimen from Vclero III Station 699-37, Angeles Channel, Gulf of California, 30 fms., March 18, 1937. Remarks. — The name chilensis has been re-established, since it is al- most unbelievable that the species from China is identical with the Chilean form. Ludwig evidently considered the 2 species as different and then decided to unite them in spite of the differences which they ex- hibited. It is not clear from his description whether he found any cross- shaped bodies in the Chilean specimens (present in C. exigua from China). The combination of characters, viz., simple ring and small ven- tral tentacles and the unusually narrow supporting rods in the feet, is such that it seems almost certain that the present species is identical with the one described by Ludwig. Most of the plates found in the Velero specimen are considerably more complex than indicated by Ludwig, but simple 4-holed buttons are also present, and it is well known that the spicules are often more or less reduced in this group. (The earlier authors, often on general principle, avoided figuring the more complex spicules, as study of certain holotypes has revealed, and figured only those which could be easily reproduced.) The Velero III specimen measures 3 cm. in length, but is so strongly retracted that it probably measured 10 cm. or more when expanded. Lud- wig's types measured about the same, but it is not known whether they were very strongly contracted or not. 3. Gucumaria dubiosa Semper Plate 11, Figs. 1-2 Cucumaria dubiosa Semper, 1868, p. 238, pi. 39, fig. 19. — Lampert, 1885, p. 151.— Theel, 1886, p. 111. Cucumaria leonina Ludwig, 1898, p. 36. — Ekman 1925, p. 52, text fig- ure 10. Nee Cucumaria leonina Semper, 1868, p. 53, pi. 15, fig. 9. Diagnosis. — Medium-sized form, length up to 10 cm. Feet in 5 bands and numerous in the dorsal interambulacra. Tentacles bushy, of unequal size. Color uniformly parchmentlike (in alcohol). Calcareous ring simple, other features as in the typical forms. Spicules numerous, oblong, knobbed plates, often with spinous handle- and 4-holed buttons. 2 In very young specimens (1 cm. long) a number of almost circular plates with a long narrow handle are found (see Ekman's text figure). Such plates with handles have not been discovered in Cucumaria lubrica from the western coast of North America. 82 ALLAN HANCOCK PACIFIC EXPEDITIONS VOL. 8 Feet with rudimentary end plate, or none at all, and numerous support- ing rods, mostly 3 armed. Introvert and tentacles with perforated plates and rods. Type. — Possibly in Germany. Type locality. — Coast of Peru. Distribution. — From Peru to the south end of South America, in- cluding Falkland Islands, also Costa Rica. See Ekman, 1925. Depth. — Not recorded for the type. Specimens examined. — Numerous from the following stations of Velero III: 365-35. Callao, Peru, of? southeast corner of Lorenzo Island, 10 fms., January 10, 1935, 21 specimens. 366-35. Callao, Peru, between rocks, south of Lorenzo Island, 8 fms., January 10, 1935, 1 young specimen. 384-35. Independencia Bay, Peru, % mile oflF shore, east side of bay, 5 fms., January 14, 1935, 1 young specimen. 466-35. Parker Bay, Costa Rica, small island at north side of bay, shore, February 9, 1935, 1 specimen. This record so far north is unusual. Remarks. — The examined specimens range in size from 1.5 cm. to 6 cm. Even the smallest individual has a number of tube feet scattered in the dorsal interambulacra and therefore cannot be mistaken for C. calif arnica of the same size ; the latter species has, moreover, darkly pig- mented tentacles. The spicules resemble those found in Cucumaria lubrica H. L. Clark (including C. fisheri Wells) from the west coast of North America, and it is rather difficult to express the differences in such variable forms. The northern form seems always to have numerous 4-holed buttons which apparently sometimes are lacking in the southern form. The name dubiosa has been preferred to leonina against such authori- ties as Ludwig (1887 and 1898) and Ekman (1925). Semper's leonina is supposed to have come from Singapore, and it is only a surmise that it is identical with C. dubiosa. Since it is very unlikely that the same species occurs in both Singapore and Chile and since the Chilean (and Peruvian) locality is above reproach, it has been concluded that the locality Singapore was wrong. But it is quite possible that C. leonina came from Singapore; species with similar spicules are known from other places, for example, C. kollikeri from the Mediterranean Sea and C. salmini from Celebes. The latter was listed by Lampert, 1885, as occur- NO. 3 DEICHMANN: HOLOTHURIOIDEA ; PART I, DENDROCHIROTA 83 ring in the Strait of Magellan, and since then it was concluded that the locality Celebes was wrong. Very likely salmini from Celebes is a syno- nym of leonina from Singapore but different from the species from Peru and Chile. 4. Cucumaria crax, new species Plate 10, Figs. 1-5 Diagnosis. — Small form (?). Skin soft, smooth; feet large, soft, completely retractile, arranged in 5 bands, apparently not present in the interambulacra. Tentacles soft, bushy, of equal size. Calcareous ring low, simple, strongly undulated posteriorly ; radials deeply incised ; a single stone canal attached in the dorsal mesentery, 2 ventral Polian vesicles. Retractors short, fleshy, gonads attached near the middle of the body. Spicules, a scattered layer of small biscuit-shaped bodies, usually with 4-8 marginal holes, frequently incompletely closed, and knobbed margin. Feet with rudimentary end plate and short 3-armed supporting rods. Introvert and tentacles, respectively, with buttons and numerous narrow rods with perforated ends, large in the stem, small and almost hair fine in the ends of the tentacles. Color mottled brown with paler ambulacra; tentacles black. Type. — Holotype, AHF no. 23, 6 paratypes. Type locality. — Station 283-34, Thurloe Point, Thurloe Bay, west coast of L. Calif., 8-10 fms., March 9, 1934. Distribution. — Known from the type locality. Depth. — From 8-10 fms. Specimens examined. — The type and 6 paratypes. Remarks. — The type measures 1.5 cm. in length and is strongly con- tracted. The gonads are well developed, but this fact in itself constitutes no clue to the size which the species may attain when full grown. Superficially it resembles a small specimen of C. calif ornica Semper, but the spicules are entirely different. If the spicules disappear completely as the animals grow larger, it may become impossible to distinguish be- tween the two forms. 5. Cucumaria godeflfroyi Semper Cucumaria godeffroyi Semper, 1868, p. 53, pi. 15, figs. 12, 14. — Lam- pert, 1885, p. 144.— Theel, 1886, p. 99.— Clark, 1910, p. 352. 84 ALLAN HANCOCK PACIFIC EXPEDITIONS VOL. 8 Nec Holothuria crocea Lesson, 1830, p. 153, pi. 52. Suggested by Semper but not accepted by later writers. Description. — Imperfectly known. Presumably the feet are restricted to the ambulacra and the tentacles probably of equal size. The calcareous ring is simple. The Polian vesicle is single; the stone canal attached in the dorsal mesentery. Spicules perforated plates with laciniated edge and one end narrower with long marginal spines, this end projecting through the skin. Type. — Hamburg. Type locality. — Iquique, Chile. Distribution. — Coast of Chile. Depth. — Not noted. Specimens examined. — None. Remarks. — No specimen seems to have been secured since the type was described. The type measured 3.5 cm. in length, possibly strongly contracted. The interambulacral feet may have been overlooked. The spicule figured could be interpreted as a degenerate plate from an aged C. dubiosa. Genus 2. PENTAMERA Ayres, 1852 Pentamera Ayres, 1852, p. 207.— Deichmann, 1938, p. 373; 1938a, p. 105. Diagnosis. — Small to medium-sized forms; ventral tentacles small; feet long, nonretractile, arranged in 5 bands but never scattered in the interambulacra. Calcareous ring with long posterior prolongations on the radials. Spicules 2-pillared tables or derivatives from these with the spire reduced or developed as acornlike bodies. Feet with large end plate and supporting tables, usually with well-developed spire; in some forms the spire is more or less completely reduced. Tentacles with rods or plates, in some forms devoid of spicules, at least in the older individuals. Spicules in most forms numerous throughout the animal's life, in some species the spicules are few and degenerate. Type species. — Pentamera pulcherrima Ayres. Remarks. — The diagnosis has been modified to include also Pentam- era chicrchia Ludwig and P. zacae Deichmann, the former with few and mostly reduced spicules, the latter with peculiar acorn-shaped bodies — as it seems unwise for the present moment to segregate these two forms which otherwise conform so well with the typical members of the genus. NO. 3 DEICHMANN: HOLOTHURIOIDEA ; PART I, DENDROCHIROTA 85 The type species seems to be the only representative known from West Indian waters, while P. calcigera (Stimpson) is widespread in the northern Atlantic and Pacific oceans, and 7 related species have devel- oped along the western coast of North America (see Deichmann, 1938). From the Panamic region (and Chile) 4 species are known. One of these is closely related to the type species. Key to the Species of Pentamera Known from the Panamic Region 1. Spicules in skin acorn-shaped bodies, possibly derived from tables. Feet with end plate and curved supporting tables with well-developed spire. Color white 1. Pentamera zacae Deichmann 1. Spicules in skin 2-pillared tables or derivatives of these (with spire reduced to knobs or spines) 2 2. Spicules scattered, tables reduced to disks with spinous edge and mostly with 2 knobs or spines indicating the spire. Feet with large end plate and a few spectacle-shaped rods, rarely any trace of a spire. Color dark brown to black 3. Pentamera chierchia (Ludwig) 2. Spicules crowded tables with well-developed spire, disk with smooth edge. Feet with end plate and supporting tables with well-developed to excessively developed spire 3 3. Supporting tables in feet partly with excessively tall spire. Tables small 2. Pentamera beehei Deichmann 3. Supporting tables in feet with moderately tall spire. Tables not small 4. Pentamera chiloensis (Ludwig) 1. Pentamera zacae Deichmann Plate 12, Figs. 10-17 Pentamera zacae Deichmann, 1938, p. 375, text fig. 9. Diagnosis. — Small form (few cm. long) body strongly curved, taper- ing toward both ends. Feet cylindrical, non retractile, in 5 bands, most numerous on the ventrum, more scattered on the dorsum and toward the oral and anal ends. Spicules a crowded layer of peculiar small bodies re- sembling acorns, with a tapering spire, mostly composed of 2 rods and a basal cup-shaped part. Feet with large end plate and numerous support- 86 ALLAN HANCOCK PACIFIC EXPEDITIONS VOL. 8 ing tables with curved disk with 4 central holes and a small hole in each end, spire with 2 pillars and ending in a few lobes or blunt teeth which lie in one plane. Color white. Type.— M.C.Z. Type locality. — Zaca Sta. 196 D-17. Distribution. — Tangola Tangola Bay, Mex. Depth. — From 23 fms. Specimens examined. — The type. Remarks. — The type measures about 3 cm. in length. The skin is rigid with spicules. The oral end with the tentacles and calcareous ring is lost as well as most of the inner organs. It is therefore only tentatively that the species is referred to Pentamera. 2. Pentamera beebel Deichmann Plate 12, Figs. 1-9 Pentamera beebei Deichmann, 1938, p. 374, text fig. 7. Diagnosis. — Typical small pentamerid with minute tables (diameter 0.03 mm.) with mostly 4 larger holes and 4 smaller ones; spire 2 pil- lared, ending in a tuft of spines. Feet with large end plate and curved supporting tables with from 2-7 crossbeams in the spire and a terminal tuft of flat lobes. Color white. Type.— M.C.Z. Type locality. — Zaca Sta. 213 D-15. Distribution. — Known from Ballena Bay, Gulf of Costa Rica. Depth. — From 40 fms. Specimens examined. — The type. Remarks. — The type measures few cm. in length. Its striking spicules set it apart from all other species known from the Panamic waters. 3. Pentamera chierchia (Ludwig) Plate 13, Figs. 19-21 Cucumaria chierchia Ludwig, 1887, p. 13, pi. 1, fig. 5. Pentamera chierchia Deichmann, 1938, p. 374, text fig. 8. Diagnosis. — Small form (about 3-4 cm. long) with numerous feet in 5 narrow bands. Calcareous ring with long posterior prolongations. Spicules in varying numbers, in some individuals almost completely lack- ing. Skin with 4-holed tables with dentate margin and 2-pillared spire with few irregular teeth; often the spire is reduced to knobs or com- NO. 3 deichmann: holothurioidea; part i, dendrochirota 87 pletely lacking. Feet with large end plate and a va^'ing number of mostly spectacle-shaped rods, often with 4 central holes incomplete or complete, and a number of smaller holes in the ends. Introvert with a few tables. Tentacles with curved perforated plates and rods. Color black, rarely brown with pale underside. Type. — Possibly in Germany. Type locality. — Coast of one of the islands in the Gulf of Panama. A single specimen secured. Distribution. — From Ecuador and Galapagos to L. Calif. Depth. — Shore to 40 fms. Specimens examined. — The following from the Allan Hancock Expe- ditions : 73-33. North Beach, Cartago Bay, Albemarle Island, Galapagos, shore, February 13, 1933, 22 specimens. 80-33. Smitty's Shore, Duncan Island, Galapagos, shore, February 15, 1933, 15 specimens. 132-34. Braithwaite Bay, Socorro Island, Mex., 40 fms., January 4, 1934, 13 young specimens. 189-34. Cartago Bay, Albemarle Island, Galapagos, shore, January 25, 1934, 5 specimens. 315-35. Indefatigable Island, opposite Gordon Rocks, coral, 1-2 fms., December 8, 1934, 3 specimens. 401-35. Manta, Ecuador, below first rocky point, 1 fm., January 19, 1935, 5 specimens. 464-35. Playa Blanca, Costa Rica, 2 clumps of coral, south shore of bay, shore, February 8, 1935, 2 specimens. 467-35. Parker Bay, Costa Rica, rock and algae, 2 fms., February 9, 1935, 2 specimens. 473-35. Parker Bay, Costa Rica, coral, 2 fms., February 9, 1935, 39 specimens. 596-36. Port Escondido, L. Calif., 20 fms., March 16, 1936, 1 speci- men. 683-37. Outside of Concepcion Bay, L. Calif., Mex., 12 fms., March 15, 1937, 17 specimens. 784-38. Darwin Bay, Tower Island, Galapagos, Middle Beach, shore, January 17, 1938, 7 specimens. Also several from the Zaca expedition, 1938. Remarks. — Apparently one of the most common forms in the Pan- amic region. 88 ALLAN HANCOCK PACIFIC EXPEDITIONS VOL. 8 4. Pentamera chlloensis (Ludwig) Plate 13, Figs. 15-18; text figure 1 Cucumaria chlloensis Ludwig, 1887, p. 12, pi. 1, fig. 4. — Dei'chmann, 1938, p. 373, passim. Cucumaria tabulifera R. Perrier, 1904, p. 14; 1905, p. 17, pi. 1, figs. 4-5 ; pi. 3, figs. 1-5. Diagnosis. — Typical pentamerid, resembles the type species. Spicules tables with oval to squarish disk (diameter 0.06 mm.) with 4 or 8 holes; spires 2 pillared with one or two crossbeams and a few short teeth at the top. Feet with large end plate and numerous curved supporting tables with low spire with 2 pillars and a few flat teeth on the top. Introvert with rosettes ; tentacles with delicate rods. Color white. Type. — Possibly in Germany. Type locality. — Chiloe Island, Chile. Distribution. — Cape Horn and vicinity to L. Calif. Depth. — The type came from 40 m. depth ; the Velero specimens were taken at from 8-60 fms. depth. Specimens examined. — The following material from the Hancock Expeditions : 190-34. Lat. 0° 55' S., 90° 30' W., Galapagos, 58-60 fms., January 26, 1934, 1 specimen. 209-34. La Libertad, Ecuador, north of Point Sta. Elena, 8-10 fms., February 9, 1934, 1 specimen. 213-34. La Plata Island, Ecuador, north of anchorage, 7-10 fms., Feb- ruary 10, 1934, 1 specimen. 677-37. Ildefonso Island, L. Calif., Mex., 50 fms., March 15, 1937, 3 specimens. 833-38. Independencia Bay, Peru, off north entrance, sand and shell, 8 fms., February 10, 1938, 1 specimen. Remarks. — The species resembles the type species from the AVest Indies. Ludwig's specimen measured only 9 mm., while Perrier had two specimens, 20 and 23 mm. long. The Velero material falls about within these limits. The species may be expected to reach a length of about 5 cm.; the tables in younger individuals may possibly have larger disks with 2 circles of holes; some tables have a dentate edge as if one row of holes had been resorbed. It differs from C. pulcherrima in the lack of perforated plates m the tentacles and the presence of rosettes in the introvert, and the smaller size — characters which may prove to be abso- NO. 3 DEICHMANN: HOLOTHURIOIDEA ; PART I, DENDROCHIROTA 89 I I I I I I I I Text fig. 1. Pentamera chtloensis (Ludwig) ? Spicules from juvenile individual. Scale divisions indicate Moo mm. lutely worthless. A small specimen from Sta. 190-34, 1.5 cm. long, had the genital tubes packed with ripe eggs. The very young individual from Station 209-34 had much smaller spicules than the other individuals, but it can hardly be doubted that it represents P. chtloensis. Doubtful form: Pentamera panamensis (Verrill) Ocnus panamensis Verrill, 1867, p. 321. — Lampert, 1885, p. 132. — Theel, 1886, p. 116. From Verrill's incomplete description it can only be learned that the type measured about 4 cm. in length; the feet were restricted to the ambulacra, in double rows on the ventrum, in single rows toward the ends and on the dorsum; the tentacles were 10 in number and the 2 ventral smaller. The skin was thin, coriaceous, filled with numerous minute calcareous grains or plates. The color was grayish brown, the tentacles yellowish brown. Type. — Apparently lost. Type locality. — Gulf of Panama. Distribution. — Known only from the type locality. Depth. — Presumably shallow water. Specimens examined. — None. Remarks. — This may be any of the species belonging to Pentamera, A pentamera, or Neopcntarnera, except P. chicrchia and A. lepra. The 90 ALLAN HANCOCK PACIFIC EXPEDITIONS VOL. 8 few feet on the dorsal side suggest P. heebe'i, while the description of the spicules suggests P. zacae. As it is completely impossible to place the species, the name must once and for all be rejected. Genus 3. NEOPENTAMERA, new genus Diagnosis. — Externally resembling Pentamera Ayres, with tube feet restricted to the 5 ambulacra (?). Calcareous ring with well-developed posterior prolongations. Spicules irregular, 4-holed, knobbed buttons; feet with end plate and narrow ribbonlike rods, possibly derived from tables. Type species. — Neopentamera anexigua, new species. Remarks. — The genus and species are based upon a number of small specimens, apparently adult, secured by the Hancock Expeditions. As the specimens are so small, there is of course the possibility that tube feet may appear later in the interradials, which will necessitate a modifica- tion of the diagnosis. The spicules bear some resemblance to those of Eupentacta pseudoquinquesemita Deichmann from the coast of Alaska but are so much smaller that I have felt justified in establishing a new genus for this species. It cannot be confused with any other dendrochirote form hitherto recorded from the Panamic region. Neopentamera anexigua, new species Plate 13, Figs. 11-14 Diagnosis. — Small form (few cm. long), externally as internally a typical pentamerid. Spicules numerous, irregularly knobbed buttons or plates. Feet with large end plate and ribbonlike supporting rods with no indications of a spire. Introvert with plates and rosettes. Tentacles with rosettes and delicate rods derived from rosettes. Tentacles dark brown. Color white. Type. — Holotj^pe, AHF no. 24, one paratype. Type locality. — Velero III Station 683-37, outside of Concepcion Bay, L. Calif., Mex., 12 fms., March 15, 1937. Distribution. — Known only from the type locality. Depth. — Taken at 12 fms. depth. Specimens examined. — The type and a paratype. Remarks. — The types are poorly preserved and measure only 2 cm. NO. 3 DEICHMANN: HOLOTHURIOIDEA ; PART I, DENDROCHIROTA 91 in length. In the type the gonads are large ; many tubes measure almost 2 cm. ; presumably it is a male, as no traces of eggs were seen. It is possible that an external layer of more delicate spicules normally is present but has been destroyed. The spicules are slightly reminiscent of those characteristic of Eupentacta pseudoquinquesemita Deichmann, from the Alaskan waters, but they are smaller, and the tails on the cal- careous ring are distinctly longer in the present species. The name anexigiia is given because it was at first glance assumed that the present species was identical with Ludwig's Cucumaria exigua from China and, supposedly, also Chile (see p. 81). The species from Chile is now called C. chilensis, as indicated in Ludwig's figures; it was actually rediscovered by the Allan Hancock Expedition (see p. 80). Dissection revealed, however, that the calcareous ring was entirely dif- ferent — with long tails — and the species must therefore be regarded as new. Genus 4. APENTAMERA, new genus Diagnosis. — Small forms (few cm. long) with tube feet in 5 bands, papilliform toward the ends where 5 valves are formed ; a few smaller papilliform tube feet are scattered in the dorsal interambulacra, may be lacking in small individuals. Tentacles 10, the 2 ventral smaller. Skin rigid, packed with spicules. Calcareous ring with long posterior prolon- gations; other internal features almost as in Pentamera. Spicules an external layer of flattened baskets almost rosettelike, easily overlooked and may possibly be lost in older individuals, and an inner layer of regular 4-holed knobbed buttons. Feet with end plate smaller in the terminal appendages; walls packed with curved supporting tables with 2 pillars and a few blunt teeth. Introvert with oblong tables or plates with slightly knobbed edge. Tentacles packed with plates and rods which gradually decrease in size in the branches; apparently no rosettes. Type species. — Apentamera lepra, new species. Remarks. — The material of the type species was originally referred to 2 genera related respectively to Pentamera and Pentacta, possibly with affinities to some of the Thyone-\\\it forms. After all other species had been classified, it became evident that these two "genera" represented only one, which in spite of its affinities to the Thyone-\\\ic forms could not be placed among these. 92 ALLAN HANCOCK PACIFIC EXPEDITIONS VOL. 8 Apentamera lepra, new species Plate 13, Figs. 1-10 Diagnosis. — As for the genus. Color white, mottled with reddish brown. Type. — Holotype, AHF no. 25. Type locality. — Station 557-36, off White Rock, Isla Partida, Gulf of Calif., in 45 fms., March 8, 1936. Distribution. — Gulf of Calif, to Panama. Depth. — From 30-50 fms. Specimens examined. — The following material from the Hancock Expeditions : 557-36. Isla Partida, Gulf of California, 45 fms., type and 2 paratypes. 863-38. Bahia Honda, Panama, off North Island, 30-50 fms., March 1, 1938, 3 specimens (M.C.Z.). Remarks. — The type specimens measure 3.5, 3.4, and 2.0 cm. in length ; the gonads are well developed in the 3 individuals, so presumably the animals are full grown. The material has been carefully compared with the other forms with 4-holed knobbed buttons, but it seems impos- sible that it represents the juvenile stages of any of these. The only form which possibly could be considered is Neothyone gibbosa (see p. 113), but the latter has numerous interambulacral feet when it is as large as A. lepra, and its spicules are definitely larger; the buttons are more ob- long and it has numerous rosettes in the tentacles. Genus 5. LEPTOPENTACTA H. L. Clark, 1938 Synonym. — Ocnus Auctores. Nee Ocnus Forbes, 1841. See H. L. Clark, 1938, p. 453. Diagnosis. — Body slender, skin rigid. Tentacles 10 (or 8), the ven- tral ones small (or lacking). Feet restricted to the ambulacra, rigid, filled with spicules, arranged either in single rows with feet well spaced or in more crowded or zigzaggy rows. Toward the oral and anal ends the feet are scattered and papilliform, often forming 5 valves as in Pentacta. Cal- careous ring simple, or with short posterior prolongations. Retractors short, longitudinal musculature feebly developed. Gonads with few tubes in each tuft, attached near the middle of the animal. Spicules reticulated bodies or baskets, larger or smaller, reticulated scales or grains and 4-holed buttons, swollen or knobbed. Feet with or without end plate, with or without supporting rods. Tentacles with large perforated rods or plates ; sometimes also rosettes and smaller rods. NO. 3 deichmann: holothurioidea; parti, dendrochirota 93 Type species. — L. grisea H. L. Clark, 1938. Remarks. — The genus may possibly be further divided into two, viz., Leptopentacta, which includes the type species, L. panamica spec, nov., possibly also Sluiter's "Ocnus" javanicus, and a species listed here as L. nina, based on a juvenile individual from the Hancock Expeditions, — and another, for which the name Parocnus is proposed, — to accommodate "Ocnus" imbricatus Semper and "Ocnus" typicus Theel, which possibly are identical, and L. nova, spec. nov. 1 Text fig. 2. 1. Calcareous ring from Leptopentacta grisea H. L. Clark. 2. Leptopentacta panamica, new species. 3. Leptopentacta javanica (Sluiter). Scale, 1 mm.; Sluiter's figure has no indication of what magnification is used; probably it is about as large as the other two. "Ocnus" molpadioides Semper definitely does not belong in this genus, while "Ocnus" pygmaeus Semper, based upon a specimen 1 cm. long, has long and rather flexible feet and probably represents a juvenile specimen of some species of Cucumaria or Thy one (in the broad sense). It is not possible to ascertain whether the calcareous ring is simple or has pos- terior prolongations. Semper figures a simple ring but mentions that the ring has long posterior prolongations. His figures of the ring of imbricata show no posterior prolongations, and in his description he emphasizes the way in which the ring is cut off posteriorly. (See footnote, p. 94.) Key to the Known Species of Leptopentacta 1. External layer of spicules consisting of small biscuit-shaped plates or rosettes. Feet with no supporting rods, and apparently without end plate. Calcareous ring simple (not known in L. typica) 94 ALLAN HANCOCK PACIFIC EXPEDITIONS VOL. 8 1. External layer of spicules consisting of baskets, reticulated bodies, or hollow plates. Feet with supporting rods or plates, in some species also with end plate. Calcareous ring with short tails 4 2. External spicules consisting of small biscuit-shaped bodies with 4-5 holes, often one side prolonged into a sharp tooth. Feet few, scattered, 5-6 in the dorsal ambulacra, 8-10 in the ven- tral ones 1. Leptopentacta nova, new species 2. External spicules consisting of rosettes. Feet fairly numerous, although arranged in single rows 3 3. Feet 24-26 in the ambulacra (in individuals 35-40 mm. long). Leptopentacta i/nbricata (Semper) 3. Feet 15-20 in the ambulacra (in individuals 40 mm. long). Leptopentacta typica (Theel) 4. External spicules consisting of simple, 4-spok:ed, deep baskets with knobbed to dentate rim. Feet with numerous supporting rods or plates 5 4. External spicules consisting of complicated reticulated bodies or concave plates 6 5. Buttons swollen or irregularly knobbed. Baskets comparatively large and delicate, with 4 marginal holes Leptopentacta grisea H. L. Clark 5. Buttons predominantly strongly knobbed and regular. Bas- kets small, not delicate, and apparently never with marginal holes 2. Leptopentacta panamica, new species 6. External spicules reticulated bodies^ ; feet 20-23 in ventral rows (in individual, 40-45 mm. long) Leptopentacta javanica (Sluiter) 6. External spicules large concave plates with a varying amount of reticulated bars. Inner layer knobbed buttons slightly ir- regular and large reticulated plate. Feet with oblong support- ing plates smooth or knobbed, with a varying number of holes. 3. Leptopentacta nina, new species 3 Sluiter's figure (1880, pi. 4, fig. 10) looks suspiciously as if it belonged to a Paracaudina. His description is not very clear, and in 1901, p. 79, he writes "javanica with typica and imbricata," following Ludwig, 1837, p. 1221 (reprint p. 5). If one can trust Semper's figure (plate 14, fig. 12), imbricata must be different from javanica, as it has a simple calcareous ring. Although Ludwig's "imbricata" has distinct tails on the ring, it is not proved that it is identical with Semper's species or with Theel's. NO. 3 DEICHMANN : HOLOTHURIOIDEA ; PART I, DENDROCHIROTA 95 1 . Leptopentacta nova, new species Plate 14, Figs. 13-22; text figure 3 Diagnosis. — Body slender, slightly curved with rigid body wall. Feet few, contracted into conical protuberances, well spaced. The ventral am- bulacra possess from 8-10 feet, while the dorsal ones each have 4 feet anteriorly and one or two posteriorly. Skin with large cobblestone-like scales, and the space between them filled with masses of smaller spicules. Tentacles fingerlike (in the type which measures 2 cm. in length) and apparently only 8 are present, but the 2 small ones may have been over- looked. Calcareous ring low, with no indication of posterior prolonga- tions. Inner anatomy not remarkable in any respect. Spicules large scales or grains with reticulated structure, 4-holed but- tons, irregular, swollen or with irregular knobs, and minute perforated biscuit-shaped plates with 4-5 holes and frequently a long spine developed on one side. Feet with no supporting plates and apparently no end plate. Introvert with reticulated plates which intergrade into rosettes; tenta- cles with curved perforated or branching rods which decrease in size toward the ends. Type. — Holotype, AHF no. 26, 1 paratype. Type locality. — Station 281-34, Santa Maria Bay, west of Hughes Point, L. Calif., 35-40 fms. Text fig. 3. Leptopentacta nova, new species. Scale, 1 mm. 96 ALLAN HANCOCK PACIFIC EXPEDITIONS VOL. 8 Distribution. — Known from the type locality. Depth. — Dredged at 35-40 fms. Specimens examined. — The type. Remarks. — The type and other specimen measure 2 cm. in length and 3 mm. in width. The surface of the skin appears mottled, because of the large scales' being glassy and contrasting with the solid white of the smaller spicules which are massed between them. The tentacles which are completely retracted are small and finger shaped ; only 8 could be counted, but 2 small ones may possibly have been overlooked. The cal- careous ring is low with no indication of posterior prolongations; the stone canal is small and attached as usual in the dorsal mesentery, and the Polian vesicle is single and ventrally placed. Other anatomical fea- tures are not remarkable. The gonads form few tubes of varying length, and are attached near the middle of the dorsal midline. This species seems most closely related to L. imbricata (Semper) and L. typica (Theel). It differs in having small biscuit-shaped plates in- stead of rosettes in the external layer of the skin, fewer feet, and, presum- ably, in having simple tentacles. However, L. nova, L. imbricata (and L. typica) may well be placed in a separate genus for which the name Parocnus is proposed, with imbricata as type. 2. Leptopentacta panamica, new species Plate 14, Figs. 6-12; text figure 2 Diagnosis. — Slender form with curved body, ambulacra forming 5 indistinct ridges. Feet in scattered double rows in the middle portion of the ambulacra, toward the ends in single rows, around the base of the introvert forming 5 large valves as in Pentacta. Tentacles 10, bushy, the 2 ventral smaller. Surface of skin rough on account of the numerous spinelike projections on the spicules which pierce the skin. Calcareous ring with short posterior prolongations. Other features also typical of the genus. Spicules consisting of an external layer of strongly knobbed 4-holed buttons with minute holes and smaller buttons, less strongly knobbed and with larger holes and numerous 4-spoked baskets, and an inner layer of large, reticulated ovoid or spherical scales or grains. Feet possibly with an end plate (not discovered in type)^ and numerous perforated supporting 4 The type species has a large and well-developed end plate in the feet (over- looked by H. L. Clark), and one would expect that an end plate would also be present in the present species. Two tube feet have been examined, but the feet are strongly contracted and no trace has been found of end plates. Still it is pos- sible that they may be present. NO. 3 DEICHMANN : HOLOTHURIOIDEA ; PART I, DENDROCHIROTA 97 plates, and the same type of spicules as in the integument. Particularly numerous in the appendages, although also scattered in the skin are some peculiar oblong heavy plates with small holes and one end drawn out into a shorter or longer spine which pierces the skin (visible with low magnification). Introvert with rosettes, tentacles with large curved per- forated plates and rods, also rosettes, and in the finer branches, delicate rods with perforated ends. Ty/.^.— Holotype, AHF no. 27. Type locality. — Port Utria, Colombia, close to shore, north of point and west of islands, 20 fms., January 25, 1935. Distribution. — From Port Utria, Colombia, to Tenacatita Bay, Mex. Depth. — From 20-35 fms. Specimens examined. — The type and 3 other specimens from the fol- lowing Velero stations: 259-34. Tangola Tangola, Mex., 15-20 fms., February 28, 1934, 1 paratype. 275-34. Tenacatita Bay, Mex., of? Navidad Head, 25-35 fms., 2 speci- mens. 423-35. Port Utria, Colombia, close to shore, 20 fms., 1 specimen, type. Kemarks. — The type measures about 4 cm. in length ; the other indi- viduals are smaller. The color in alcohol is dirty yellow with large ir- regular brown patches. The gonads are ripe and filled with eggs. (Speci- mens collected in January.) The species seems fairly closely related to the type species, L. grisea H. L. Clark, from Broome, West Australia (plate 14, figures 1-5). It differs chiefly in the presence of the peculiar, spine-bearing plates, the strongly knobbed buttons, and the much smaller and more simple baskets. 3. Leptopentacta nina, new species Plate 15, Figs. 1-12 Diagnosis. — Small form (?), type measures 1.2 cm. with the tenta- cles contracted. Body curved, slender; skin rigid; feet cylindrical, re- tractile, restricted to the ambulacra (the type has about 25 tube feet in the ventral rows and considerably fewer in the dorsal). Calcareous ring with distinct posterior tails on the radials and long teeth, deeply grooved on radials and interradials (resembles that of Sluiter's species, see text figure 2). 98 ALLAN HANCOCK PACIFIC EXPEDITIONS VOL. 8 Spicules an external layer of concave plates, often with a delicate reticulum across the hollow surface; an inner layer of knobbed, irregular buttons, and larger plates with knobbed surface, sometimes transformed into large convex bodies. Feet apparently devoid of end plate ; walls with short, broad, perforated supporting rods. Introvert and tentacles not examined. Color of the preserved specimens white. Tj;^^.— Holotype, AHF no. 28. Type locality. — Station 850-38, Cape San Francisco, Ecuador, 15 fms., February 23, 1938. Distribution. — Known only from the type locality. Depth. — From 15 fms. Specimens. — The type. Re?narks. — The type represents undoubtedly an immature individual. On account of its small size and its rigid skin it was almost impossible to dissect, and no attempt was made to study the tentacles and introvert. The inner organs were poorly preserved, and nothing can be said about the stone canal and Polian vesicle. The musculature is feebly developed, and the intestine and respiratory trees form a structureless mass; a well- developed muscle stomach could, however, be seen. The calcareous ring is highly reminiscent of the one figured by Sluiter for javanica (see text figure 2), and it is of course remotely possible that the present species has previously been described from the East Indies. As the various earlier descriptions are rather unsatisfactory, as also the figures hitherto pub- lished, it has been deemed wiser to designate the unique individual to a new species. L. nina differs distinctly from both L. nova and L. panamensis in its calcareous ring as well as in its spicules. It cannot be confused with any other species at present described from the Panamic region. Genus 6. PENTAGTA Goldfuss, 1820 Pentacta Goldfuss, 1820, p. 177.— H. L. Clark, 1923, p. 416. Colochirus Troschel, 1846, p. 64. (Type species. — C. quadrangularis Troschel.) Cercodemas Selenka, 1867, p. 343. (Type species. — C. anceps Selenka.) Diagnosis. — Body with more or less flattened ventral side with the tube feet arranged in 3 bands ; dorsal side vaulted with feet of different size, often as large papillae, frequently scattered in the interambulacra. Around the base of the introvert and the anus the ambulacra form thick NO. 3 DEICHMANN: HOLOTHURIOIDEA ; PART I, DENDROCHIROTA 99 valves. Tentacles 10, the 2 ventral smaller. Skin rigid, filled with spicules. Calcareous ring simple, posteriorly often strongly undulated but never with posterior prolongations. Spicules consisting of an external layer of either baskets or delicate reticulated bodies, and inner layer of knobbed buttons, heavy plates, or reticulated bodies. Feet apparently with no end plate; walls supported by perforated rods or plates; dorsal papillae with mostly curved sup- porting plates. Tropical shallow water forms. Type species. — Pentacta doliolum (Pallas). Remarks. — The name has been used by various authors for members of the genus Cucumaria s.l., and Ludwig (1899, p. 344) claims that it ought to be used instead of Blainville's name, from 1835. H. L. Clark (1923, p. 416) has, however, called attention to the fact that Troschel's name Colochirus is a complete synonym of Pentacta, for Goldfuss desig- nated Pallas' doliolum from Cape of Good Hope as the type species and the latter is generally accepted as the typical "Colochirus." The genus Pentacta is most abundantly represented in shallow water in the East Indies. The type species represents the only form known from the South African waters, and only one form is known from Brazil and the West Indies. From the western coast of South America Semper de- scribed a new species which was never found again and hence was re- garded as rather dubious. There is no doubt that it is the one which the Allan Hancock Expeditions now have brought back, thereby proving that Semper's specimens were correctly labeled. The genus may possibly in the future be divided into 2, viz., one for those with more complicated spicules, and one for those with regular, knobbed buttons and simple baskets. The 2 species known from the American waters both belong to the latter group. Pentacta peruana (Semper) Plate 16, Figs. 1-8 Colochirus peruanus Semper, 1868, p. 239, pi. 39, fig. 20. — Lampert, 1885, p. 126.— Theel, 1886, p. 123.— H. L. Clark, 1910, p. 353. Diagnosis. — Small form, few cm. long, with cylindrical feet in 3 crowded bands on the greater part of the ventral side, transformed into papillae toward the ends, dorsally 2 bands of papillae and a number scattered in the interambulacra. Oral and anal ends closed by 5 distinct valves. Inner anatomy typical of the genus. ^^- 100 ALLAN HANCOCK PACIFIC EXPEDITIONS VOL. 8 Spicules an external layer of regular baskets, the hollow part formed by broad bars, the narrow rim with few teeth. An inner layer of regular 4-holed knobbed buttons and larger knobbed plates and huge reticulated grains. Ventral feet mostly with a minute end plate and the walls packed with supporting rods mostly 3-armed, smooth to knobbed. Dorsal ap- pendages apparently lacking end plate but with heavier 3-armed rods. Introvert with a few oblong buttons smooth or knobbed. Tentacles with stems packed with narrow plates or rods, smaller, curved and often 3- armed rods in the finer branches. Type. — Possibly in Germany. Type locality. — Peru, probably at comparatively low depth. Distribution. — From Peru to Mexico. Depth. — The Hancock material came from 25 fms. Specimens examined. — The following specimens from the Allan Han- cock Expeditions: 264-34. Petatlan Bay, Mexico, 25 fms., south and west of White Friars Island, rock with gorgonids, 4 specimens. Remarks. — The 4 specimens measure between 3-4 cm. in length and are thus somewhat larger than the types which measured only 15-18 mm. Semper's description is not veiy detailed,^ and his figure of a basket shows a more irregular type than the one which commonly occurs. He mentions hollow knobbed bodies and large smooth plates, the latter re- ferring possibly to the smooth supporting plates. He gives, however, no reference to the regular 4-holed knobbed buttons, possibly because he considers them growth stages of the larger knobbed bodies; also they may possibly be more scarce in younger individuals. It must further be mentioned that the ventral tentacles in the present material are very slightly smaller in size than the other. 5 Semper's original description: "Zehn Tentaklen, die zwei ventralen kleine. Habitus Ascidien-artig. Auf den Riicken stehen die Ambulacral-papillen regellos zerstreut, am Bauche in drei deutlichen Reihen, deren jede zwei Fiisschen in der Breite zeigt. Es bleibt sich eine Art Bauchscheibe dadurch das die Fiisschen hinten in Ambulacral-papillen iibergehen. Farbe gelblich (im Spiritus). Drei Exsemplare, 15-18 mm. lang, 6-7 mm. breit. Am Gefassring eine einzige Polische Blase, eine kleine dorsaler Steinkanal. Lungen fast so lang wie der Korper, mit wenig, aber sehr langen einfachen Nebenasten. Geschlechtsteile zwei Biischel sehr kleiner unveriistelter Schlauche, ihre Basis am Mesenterium sehr weit nach vorne, vor dem Wassergefassring. Kalkring aus 10 einfachen Gliedern bestechend; die Radialen et^vas breiter als die Interradialen, nicht nach hinten verlanget. Keine Kaumagen. Die Retraktoren inserieren sich in der Mitte des Korpers. Grosse glatte Kalkplatten in der ganz starre Haut, dariiber ein Schicht durchbrochenene, etwas knotiger Halbkugeln." NO. 3 DEICHMANN : HOLOTHURIOIDEA ; PART I, DENDROCHIROTA 101 One specimen, which was opened, had few but well-developed genital tubes. The color of the 4 individuals is light brown with darker freckles; the general impression of the preserved material is a nondescript grayish- brown color. Genus 7. THYONACTA, new genus Diagnosis. — Medium-sized to large form, 10-15 cm. long in con- tracted condition. Skin thick, filled with spicules. Tube feet in 5 bands and in varying number in the interambulacra, depending on the animal's age ; toward the oral and anal ends thickened valves are developed. Many tube feet are conical, papilliform. Tentacles 10, the 2 ventral smaller. Calcareous ring low but with short posterior projections; stone canal small, attached to the dorsal mesentery; Polian vesicle single, ventral in position ; retractors exceptionally short, attached closely behind the cal- careous ring (when the crown of tentacles is withdrawn). Gonads placed unusually far back, in the posterior third of the body. Spicules consist of an external layer of simple baskets, and an inner layer of 4-holed buttons of different size, also a few larger plates ; mostly regularly knobbed. Feet apparently without any end plate (at least in larger individuals) ; walls with numerous supporting rods and plates besides buttons and baskets. Introvert with rosettes ; tentacles with large, mostly narrow perforated plates and rods which decrease in size toward the tips of the branches. Type species. — Thyonacta sabanillensis (Deichmann). Remarks. — ^At present 2 species have been referred to this genus, both restricted to the American waters. Very likely some of the members of the old genus Thyone from the western Pacific and Indian oceans ought to be transferred to this genus. The type species came from the West Indian seas, while the other species, described below, has been secured from various localities in the Panamic region. Thyonacta mexicana, new species Plate 17, Figs. 1-13 Diagnosis. — As for the genus. Spicules rather stout and deep baskets and buttons of 2 types, a large and strongly knobbed one and a smaller, less regularly knobbed and often with accessory holes. Color varying shades of brown. 102 ALLAN HANCOCK PACIFIC EXPEDITIONS VOL. 8 Type. — Holotype, AHF no. 29, 5 paratypes. Type locality. — Station 633-37, San Gabriel Bay, Espiritu Santo Island, L. Calif., 18 fms., March 6, 1937. Distribution. — Widespread in the Gulf of California and as far as Panama. Depth. — From 10-35 fms. Specimens examined. — The type and 5 specimens from the following Velero stations : 244-34. Bahia Honda, Panama, 30-35 fms., February 21, 1934, 1 speci- men. 554-36. Parallel to Angel de la Guardia Island, east side, 10 fms., March 8, 1936, 2 specimens. 562-36. North of San Esteban Island, L. Calif., 20-70 fms., March 10, 1936, 1 specimen. 633-37. San Gabriel Bay, Espiritu Santo Island, L. Calif., 18 fms., March 6, 1937, 1 specimen. 719-37. Consag Rock, L. Calif., 10-25 fms., March 24, 1937, 1 speci- men. Remarks. — The material shows to perfection how impossible it is to give an exact description of the general appearance of most holothurians. Two individuals are well expanded with tapering bodies, one is con- tracted to a short Pentacta-\\kt form, and two resemble slightly deformed oranges. The spicules, however, are completely identical, and a closer study of the anatomical features, calcareous ring, etc., showed that the specimens also in these respects are alike. T. mexicana is closely related to the type species but differs distinctly in the shape of the spicules. The extremely deep baskets and the large strongly knobbed buttons alone are sufficient to distinguish the present species from all other related forms known from the Panamic region. Genus 8. THYONE Oken, 1815 Thy one Oken, 1815, p. 351. Anaperus Troschel, 1846, p. 60 (partim). Diagnosis. — Small to medium-sized forms (rarely more than 10 cm. long, many species smaller). Body thin skinned with numerous nonre- tractile fairly delicate feet, most numerous ventrally. Tentacles 10, the 2 ventral smaller. Calcareous ring with long posterior prolongations on the radials. NO. 3 DEICHMANN: HOLOTHURIOIDEA ; PART I, DENDROCHIROTA 103 Spicules small 2-piIlared tables or derivatives of these. Feet with large end plate and numerous curved supporting tables usually with a well-developed spire, which in some forms, however, is completely re- duced. Tentacles with delicate rods and often rosettes. Spicules gradually reduced with age in certain species. Type species. — Thyone fusus (O. F. Miiller). Remarks. — The genus is well defined and corresponds to Pentamera in Cuctimaria sensu latiore. It is sometimes almost impossible to identify very young specimens of Pentamera and Thyone, as the latter passes through a Pentamera-stage. Fortunately that stage seems to be so short that one usually is able to find a few feet in the interambulacra. When dealing with specimens less than 1 cm. long, it is, however, wise to con- sider all the species of Pentamera and Thyone which are known in the region under consideration. Often the spicules in the introvert and ten- tacles differ in species which have spicules in the body wall which are alike, but this character cannot always be relied upon. The type species is common in the eastern and northeastern part of the Atlantic Ocean, while a closely related species is known from the West Indies, but not reaching the coasts of New England ( T. fusus ? Deichmann, 1930, p. 167). Another species with more robust tables, often with a handle on the inner side of the buttons, is likewise known from the West Indies (T. pseudofusus Deichmann, 1930, p. 168). From the Panamic region the Hancock Expeditions have secured 3 new species, while a fourth was in the M.C.Z., collected by the Stranger. Of these 4 species, 2 are closely related to the West Indian species men- tioned above. Key to the Species of Thyone s. str. Known from the Panamic Region 1. Tables delicate with 4 to 8 holes; disk oval or squarish; spire of medium height usually with 6 diverging teeth. Sup- porting tables with spire completely reduced ; disk curved, with 4 central holes and ends expanded with a varying number of minute holes 1. Thyone neofusus, new species 1. Tables more or less stout; supporting tables in tube feet with well-developed spire 2 2. Disk of table medium-sized to large, round, squarish, or oblong, with numerous holes and often with a few knobs or the entire 104 ALLAN HANCOCK PACIFIC EXPEDITIONS VOL. 8 margin distinctly thickened ; spire in most cases low, in process of becoming vestigial; supporting tables with an enormous conical spire 4. Thyone strangeri, new species 2. Disk of tables small, oval or squarish in outline, with 4-8 holes, in some cases the disk is lozenge shaped with a few small holes in the ends; no knobs 3 3. Disk oval or lozenge shaped ; spire moderately well developed, mostly with few, indistinct teeth. Supporting tables with 2 pillars which unite into a tapering cone ending in 2 small di- verging teeth (often broken off) 2. Thyone bidentata, new species 3. Disk oval with 4 central holes and a "handle" on the inner side ; spire tapering with 3-4 small teeth at the top ; support- ing tables with 2-3 pillars in the spire which ends in 2-3 teeth. 3. Thyone parafusus, new species 1. Thyone neofusus, new species Plate 18, Figs. 1-6 Diagnosis. — Small form (few cm. long?) ; feet delicate in 5 indis- tinct bands and scattered in the interambulacra. Calcareous ring typical; single small stone canal and single ventral Polian vesicle. Spicules delicate tables with 4-8 holes and 2-pillared spire. Feet with large end plate and numerous curved supporting plates or rods with 4 central holes and a varying number in the expanded ends and no trace of a spire. Introvert with rosettes; tentacles with delicate rods and ro- settes. Color of the preserved specimens white. Type. — Holotype, AHF no. 30, 2 paratypes. Type locality.— Station 190-34, Lat. 0° 55' S.; Long. 90° 30' W.; 58-60 fms. Distribution. — Off the Galapagos and vicinity. Depth.— From 20-60 fms. Specimens exarnined. — The type and the following specimen from the Velero Expeditions: 190-34. Lat. 0° 55' S.; Long. 90° 30' W.; 58-60 fms., January 26, 1934, 1 specimen, type. 814-38. North of Hood Island, Galapagos, 20-40 fms., January 28, 1938, 2 specimens. Remarks. — The type measures about 2 cm. with the tentacles with- drawn. The gonads form 2 well-developed tufts ; so the animal may pos- NO. 3 DEICHMANN : HOLOTHURIOIDEA ; PART I, DENDROCHIROTA 105 siblj' have reached its full size. Other members of the genus, as for ex- ample Thyone fusus, reach a considerably greater length. Thyone neofusus resembles Thyone fusus? from the West Indies (Deichmann, 1930, p. 167) but differs in the complete lack of a spire on the supporting plates; this may of course be a variable character. For the present it seems natural to segregate the various forms of fusus until different material has been gathered to permit a critical survey. So far no closely related species have been reported from the Californian and Chilean waters or from Hawaii. 2. Thyone bidentata, new species Plate 18, Figs. 13-16; text figure 4 Diagnosis. — Small form (few cm. long) with delicate to fairly stout feet, often in distinct bands and also scattered in the interambulacra. Inner anatomy typical of the genus. Spicules tables with oval to lozenge- I I I I I I I I I I I I I I I I Text fig. 4. Thyone bidentata, new species, juv. 1-3. Tables from integument. 4. Supporting table from tube foot. Scale, i/ioo nim. shaped disk with 4 central holes (and a few holes in the ends when the disk is lengthened) ; spire tapering to a cone with few teeth. Supporting tables with spire composed of 2 rods united into a slender spine, ending in 2 diverging teeth. Introvert with tables with numerous holes and low spire with diverging teeth; tentacles with a few rosettes. Color of pre- served specimens pale brown. 106 ALLAN HANCOCK PACIFIC EXPEDITIONS VOL. 8 Type. — Holotype, AHF no. 31. Type locality. — Station 275-34, Tenacatita Baj'-, Mex., dredging in 25-35 fms., March 4, 1934. Distribution. — From Gulf of Calif, to Colombia. Depth. — From 12-30 fms. Specimens examined. — ^The type and the following specimens from the Velero expeditions: 245-34. Bahia Honda, Panama, dredging 15-25 fms., February 21, 1934, 1 specimen. 249-34. Bahia Honda, Panama, 15-20 fms., February 22, 1934, 1 speci- men. 251-34. Secas Islands, Panama, dredging in 15 fms., February 22, 1934, 1 specimen. 275-34. Tenacatita Bay, Mex., off Navidad, 25-35 fms., March 4, 1934, 3 specimens, type and paratypes. 423-35. Port Utria, Colombia, close to shore, 20 fms., January 25, 1935, 1 specimen. 679-37. Outside of Concepcion Bay, Gulf of Calif., 30 fms., March 15, 1937, 1 specimen. 683-37. Outside of Concepcion Bay, Gulf of Calif., 12 fms., March 15, 1937, 1 specimen. 686-37. Concepcion Bay, Gulf of Calif., 12 fms., March 16, 1937, 1 specimen. Remarks. — The smallest paratype measures 0.5 cm. in length; the type and other larger specimens measure about 2 cm. In the smallest specimens the spicules are considerably smaller than in the larger as is so often the case, and many of the tables have a squarish disk with 4 acces- sory holes. In some of the larger individuals many tables are lozenge shaped with small accessory holes in the ends, while other individuals of the same size have almost exclusively oval disks with 4 holes. The exterior of the animals shows considerable variation in regard to the size of the tube feet, which vary from delicate to fairly stout. 3. Thyone parafusus, new species Plate 18, Figs. 7-12 Diagnosis. — Small form (few cm. long) with fairly stout feet, more or less distinctly arranged in bands and scattered in the interambulacra. Inner anatomy typical of the genus. Spicules form a crowded layer of NO. 3 DEICHMANN : HOLOTHURIOIDEA ; PART I, DENDROCHIROTA 107 tables with oval disk with 4 holes and a well-developed handle on the inner side; spire tapering, ending in a few teeth. Feet with well-devel- oped end plate and numerous supporting tables normally with 3 rods in the spire, which rapidly tapers into a short spine with a few teeth on the tip. Introvert with oblong tables with a varying number of holes. Ten- tacles packed with perforated plates of different sizes, with numerous holes; rosettes and delicate rods are present in the terminal branches. Type. — Holotype, AHF no. 32, 1 paratype. Type locality. — Station 272-34, Tenacatita Bay, Mex., 25 fms., March 4, 1934. Distribution. — Tenacatita Bay, Mex. Depth. — From 25 to 35 fms. Specimens examined. — The type and one paratype from the Velero Expeditions : 272-34. Tenacatita Bay, Mex., 25 fms., dredging off Navidad Head, March 4, 1934, 1 specimen. 275-34. Tenacatita Bay, Mex., 25-35 fms., March 4, 1934, 1 specimen, type. Remarks. — The type measures about 2 cm. with the oral end ex- panded. Several tentacles are torn off, and most of the inner organs are ejected. The spicules resemble closely those found in T. pseudofusus Deich- mann (1930, p. 168) from Yucatan, 25 fms. depth. The spicules differ in various respects; the West Indian form has tables with a short robust spire with numerous teeth and lacks apparently the numerous perforated plates in the tentacles. 4. Thyone strangeri, new species Plate 19, Figs. 1-11 Diagnosis. — Medium-sized form; numerous delicate feet scattered all over the body wall, often with conical or wartlike base. Calcareous ring with long posterior prolongations; interradials broad, more or less heart shaped, united by sutures with the radials. Stone canal small with a small head with thickened edges coiled up like a ball ; Polian vesicle single. Spicules a crowded layer of oblong tables, often with thickened edge and a varying number of knobs; number of holes in disk variable; spire small, on the verge of being reduced ; teeth almost completely lacking on ^S9-.^ 108 ALLAN HANCOCK PACIFIC EXPEDITIONS VOL. 8 the tip. Feet with large end plate and numerous supporting tables with a conical spire. Introvert with oblong tables, disk with knobbed edge and low spire. Tentacles with rosettes and delicate rods. Color brown, tentacles dark, blackish. Type.— M.C.Z. Type locality. — Isle Grande, west coast of Mexico (Lat. 170° 46' N.;Long. 101° 42' W.). Distribution. — Known from the type locality. Depth. — From 7 fms. Specimens examined. — The type. Remarks. — The type measures about 4 cm. with the tentacles with- drawn. The anterior portion is well preserved, but most of the intestine and respiratory trees are eviscerated. The gonads form well-developed tufts near the middle of the dorsal midline. The spicules are extremely characteristic and different from those found in all other species known from the Panamic region as well as the adjacent waters. Superficially they may be mistaken for those of Phylloph- orus aculeatus Ludwig, but comparison of the figures (plate 25) shows that they are entirely different. Genus 9. NEOTHYONE, new genus Stolus Selenka (partim), 1867, p. 356. Diagnosis. — Medium-sized forms with numerous feet; skin thick, packed with spicules. Tentacles 10, the 2 ventral smaller. Calcareous ring with posterior prolongations on the radials, in some species fairly short and soft, often inward curled, so that they easily escape notice. Single stone canal, one or more Polian vesicles, ventrally placed. Spicules an external layer of specially modified buttons, with spines either on the outer handle or transformed into reticulated baskets, in some cases lost with advancing age. An inner layer consisting of numerous knobbed buttons, mostly with 4 holes; knobs distinct or almost obliter- ated. Feet with large end plate and numerous supporting tables with or without a spire. Introvert with a varying amount of tables or reduced buttons; tentacles with a varying number of heavy plates or rods, some- times reduced with age. Rosettes seem to be present in certain species, at least in the younger individuals ; possibly they represent a variable char- acter. Type species. — Neothyone gibber (Selenka). NO. 3 DEICHMANN: HOLOTHURIOIDEA; PARTI, DENDROCHIROTA 109 Remarks. — The genus has been established to accommodate some of the species which have numerous buttons and distinct posterior prolonga- tions on the radials. For the present 2 species from the West Indian waters and 3 from the Panamic region are placed in the genus. Of these latter, one may possibly deserve a genus of its own. No attempt has been made to discuss the various East Indian species with similar spicules that possibly belong in the genus. Key to the Species of Neothyone Kxown from the Panamic Waters 1. Spicules large buttons, faintly knobbed; external layer of but- tons with strongly spinous handle. Feet with stout supporting tables with well-developed spire 1. Neothyone gibber (Selenka) 1. Spicules smaller or larger buttons strongly knobbed; external layer of buttons with few spines on the handle (often lost in older individuals) or transformed into baskets (the button itself is almost smooth with long delicate projections on the ex- ternal side uniting into a delicate reticulum) 2 2. Feet with large smooth supporting rods with no trace of spire (except in some of the dorsal appendages). External layer of smooth buttons modified into baskets with the external side covered by a delicate reticulum; these deposits are apparently retained throughout the animal's life 2. Neothyone panamensis (Ludwig) 2. Feet with curved, stout supporting tables with a varying amount of spire; spire often large and deformed in dorsal ap- pendages; older individuals may lack spire completely, but often one side is expanded and lobate. External layer of buttons often with a few spines on the handle but this type is often rare or lacking in older individuals; often a few concave buttons with marginal spines form a simple type of baskets 3. Neothyone gibbosa, new species 1. Neothyone gibber (Selenka) Plate 20, Figs. 1-9; text figure 5 Stolus gibber Selenka, 1867, p. 356. Thyone gibber Semper, 1868, p. 66. — Theel, 1886, p. 139. — Deichmann, 1936, p. 64 (passim). 110 ALLAN HANCOCK PACIFIC EXPEDITIONS VOL. 8 Nec Thyone gibber Deichmann. 1938, p. 376, text figure 11 (Neothyone gibbosa, spec, nov., see below). Thyone similis Lud%A-ig. 1887, p. 23, pi. 2, fig. 7. Diagnosis. — Medium-sized form, often with body strongly contracted and the blunt oral and anal ends upward cur\-ed. Calcareous ring fairly delicate with well-developed posterior prolongations on the radials; interradials narrow. Single dorsal stone canal, usually several Polian vesicles. Spicules large 4-holed buttons varying from regularly knobbed to swollen; the latter are especially characteristic of the older individuals. The 2 knobs in the center of the button are often united to a handle on both sides of the button. The external layer of buttons has normally dis- tinct teeth developed on the handle of the external side; sometimes ac- cessor}- rods from the margin of the button connect with the spines. Feet with large end plate and numerous stout supporting tables with several rods in the spire and a var5ing number of teeth on the top. Introvert with I I M I I I I I I I Text fig. 5. Neothyone gibber (Selenka), juv., still in the "Pen- tamera" stage. 1-2. Buttons. 3. Supporting table. 4. Table from introvert. 5. Plate from tentacle. 6-7. Rosette and rod from tentacle. Scale, Hoo ™ni. XO. 3 DEICHMANTN : HOLOTHURIOIDEA ; PART I, DENDROCHIROTA 1 1 1 delicate tables with low spire and lacelike disk approaching rosettes in complexity. Tentacles with perforated plates which often disappear in the older individuals; besides more delicate rods and plates in the branches, also rosettes. Color dirty white to almost black; oral end or at least the tentacles and the introvert are always dark purplish to black in color. Type. — M.C.Z. ; paratypes in Gottingen. Type locality. — Panama, depth not reported. Distribution. — Known from Acapulco, Alex., to Lobos de Afuera Island. Peru, often in the same locations as N. panarnensis (Ludwig). Depth. — Tidemark to few fms., clinging to rocks. Specimens examined. — The type and several specimens in various collections (from Acapulco, Panama, etc.). From the Velero Expeditions the following specimens have been ex- amined : 132-34. Braithwaite Bay, Socorro Island, Mex., 40 fms., January 4, 1934, 5 small specimens. 391-35. Lobos de Afuera Island, Peru, shore of main island with light- house, rocks, January 17, 1935, 34 specimens. 466-35. Parker Bay, Costa Rica, shore, February 9, 1935, 14 specimens. 473-35. Parker Bay, Costa Rica, rocks and algae, 2 fms., February 9, 1935, 2 specimens. 844-38. Lobos de Afuera Island, Peru, shore, February 14, 1938, 14 specimens. Remarks. — Selenka's description is exceedingly brief and not accom- panied by any figures. A good description and excellent figures are given by Ludwig, who described the species as Thyone similis, also from Panama. Neothyone gibber differs from the other species with knobbed buttons from the Panamic region in its larger buttons, with strong tendency to obliteration of the knobs and the presence of numerous spines on the ex- ternal handle. Deichmann referred erroneously a specimen of Neothyone gibbosa to this species (see p. 113), but the latter has verj' distinct knobs on the buttons, and these are also much smaller as shown by the figures here given. The smallest individuals, from Station 132-34, measure less than 0.5 cm., and the feet are restricted to the ambulacra. The spicules are con- siderably smaller than in the larger individuals. 1 12 ALLAN HANCOCK PACIFIC EXPEDITIONS VOL. 8 2. Neothyone panamensis (Ludwig) Plate 21, Figs. 1-6 Thy one panamensis Ludwig, 1887, p. 22. — Deichmann, 1936, p. 64 (passim) ; 1938, p. 378 (passim). Diagnosis. — Medium-sized form with numerous cylindrical tube feet on the ventrum, fewer and most papilliform on the dorsum. Calcareous ring with relatively broad radials with short posterior prolongations, often inward curved, so that they are easily overlooked. Other anatomical features as in the other species. Spicules an external layer of baskets derived from oval smooth but- tons, which on their external side develop a number of delicate projections that unite into a fragile meshwork. Spicules in the inner layer small regu- lar 4-holed buttons, strongly knobbed. Ventral feet with large end plate and numerous large, almost flat, smooth supporting plates or rods, ob- viously derived from supporting tables but with no trace of spire. In the dorsal appendages the end plate is smaller, and the supporting tables often show traces of a spire and are more curved. Introvert with delicate but- tons with various projections on the external side; tentacles normally with heavy rods or plates with numerous small holes and in the finer branches smaller, more delicate rods and plates. Apparently no rosettes. Color of dorsum and tentacles black; ventral side mostly white except near the oral and anal ends. Type. — Possibly in Italy. Type locality. — Coast of one of the islands in the Gulf of Panama. Distribution. — Ranging from Panama to Peru, often taken in num- bers with Neothyone gibber. Depth. — From tidemark to few fms. depth. Specimens examined. — The following individuals secured by the Velero Expeditions : 391-35. Lobos de Afuera Island, Peru, shore of main island with light- house, rocks, January 17, 1935, 2 specimens. 540-36. Puerto Refugio, Angel de la Guardia, Gulf of Calif., shore, March 3, 1936, 1 specimen. 844-38. Lobos de Afuera Island, Peru, shore, February 14, 1938, 13 specimens. Remarks. — The type measured only 23 mm., while the present mate- rial (which is well expanded) measures up to 6 cm. in length. It is with some doubt that the material is referred to Ludwig's species, as he main- NO. 3 DEICHMANN : HOLOTHURIOIDEA ; PART I, DENDROCHIROTA 1 1 3 tains that the calcareous ring lacks posterior prolongations, and he does not mention the difference in the form of the dorsal and ventral append- ages and the striking black and white coloration. The calcareous ring does, however, superficially look as if it lacks posterior prolongations, and the differences between the dorsal and ventral appendages and the color- ing may quite well be less pronounced in younger individuals. On the other hand, the description of the spicules shows no discrepancies, and the present species is the only "Thyone"-Uke form with such spicules as those described by Ludwig. Also it speaks in favor of the identification that it is usually found in the same localities as Neothyone gibber. Neothyone panaTnensis is easily recognized on account of its color and the arrangements of its feet. Also the spicules are very striking. The bas- kets seem to be retained throughout the animal's life and are numerous in all preparations, while the large, smooth supporting plates from the ven- tral feet form another character which is not easily overlooked. The Velcro specimens have large tufts of gonads and appear to be adult individuals. 3. Neothyone gibbosa, new species Plate 21, Figs. 7-11; Plate 22, Figs. 1-8 Thy one gibber Deichmann, 1938, p. 376, text figure 11. Nee Thyone {Stolus gibber Selenka, 1867, p. 356, now Neothyone gibber ^ see above ) . Diagnosis. — Medium-sized form superficially resembling Thyone gibber in its external and internal anatomy. Spicules an insignificant layer of shallow knobbed baskets derived from buttons, easily overlooked, and an inner layer of regular 4-holed buttons strongly knobbed mostly with handle and some with a few spines of varying size on the handle. Feet with large end plate, walls with nu- merous heavy supporting tables, mostly with low spire composed of several rods, occasionally more well-developed spire may be found ; especially in the dorsal feet in older individuals a number are developed as smooth plates often with one side expanded, with scalloped edge. Introvert with a varying number of mostly larger tables with numerous holes in the oblong disk and a low spinous spire. Tentacles with heavy perforated plates and rods decreasing in size in the branches ; in many cases also rosettes. Color in alcohol dirty gray or reddish, often darker mottled in the interambu- lacra; tentacles rather darkly colored. Type. — Holotype, AHF no. Z3. 114 ALLAN HANCOCK PACIFIC EXPEDITIONS VOL. 8 Type locality. — Station 545-36, Puerto Refugio, Angel de la Guardia Island, Gulf of Calif. Distribution. — From the upper end of the Gulf of Calif, to Mazat- lan, Mex. Specimens examined. — The type and the following individuals from the Velero Expeditions: 465-35. Playa Blanca, Costa Rica, shore, February 8, 1935, 1 specimen. 545-36. In Puerto Refugio, Angel de la Guardia Island, west of rock spit at river wash, shore, March 4, 1936, type and 4 paratypes. 591-36. Port Escondido, L. Calif., Mex., shore, March 16, 1936, 2 specimens. 844-38. Lobos de Afuera Island, Peru, shore, February 14, 1938, 1 specimen. Also a number of specimens in the M.C.Z. collection from Mazatlan, Mex., shore, Situantanejo Bay, Mex., and Costa Rica, shore. Remarks. — It is with some doubt that the present material has been referred to a new species, for the spicules are — aside from the absence of heavy plates covered by a stout reticulum — highly reminiscent of those found in Pachythyone pseudoluguhris, which is described below, and the latter does actually occur in the same localities as Neothyone gibhosa. The buttons have, however, more frequently 3 knobs on the external handle and show little tendency to become elongate as in pseudolugubris where the 2 central knobs frequently remain separate. Genus 10. PACHYTHYONE, new genus Diagnosis. — Small forms (few cm. long) with stout feet in 5 bands and numerous in the interambulacra ; dorsally and toward the ends more papilliform. Ventral tentacles smaller. Calcareous ring with short poste- rior prolongations. Single stone canal, single Polian vesicle. Gonads form- ing 2 tufts of few tubes. Spicules an external layer of oval buttons or plates with the external side covered by a dense reticulum ; an inner layer of oblong 4-holed but- tons regularly knobbed. Feet with end plate, reduced in the papilliform feet; walls supported by supporting tables with numerous rods in the reticulated spire; a few developed as plates. Introvert with oblong tables; tentacles with heavy perforated plates which gradually become smaller and more delicate in the branches. Type species. — Pachythyone rubra (H. L. Clark). NO. 3 DEICHMANN : HOLOTHURIOIDEA ; PART I, DENDROCHIROTA 115 Remarks. — Only 3 species have been referred to the genus; all are known from the western coast of North and Central Ameiica and two are viviparous. Key to the Species of Pachythyone 1. Color white ventrum and red dorsal side and ends. Spicules slightly larger and robust ; plates in tentacles mostly knobbed. 1. Pachythyone rubra (H. L. Clark) 1. Color mottled brown. Spicules more delicate; plates in ten- tacles mostly smooth 2 2. Supporting tables with strongly branching spire, even in the ventral feet. ... 2. Pachythyone lugubris (Deichmann) 2. Supporting tables with low spire, at least in the ventral feet. 3. Pachythyone pseudolugubris, new species 1. Pachythyone rubra (H. L. Clark) Plate 23, Figs. 10-12 Thyone rubra (H. L. Clark), 1901, p. 166; text figures 1-5; 1901a, p. 494. — Deichmann, 1939, p. 5 (passim) ; text figure 3. Diagnosis. — Small, robust form, few cm. long, with stout cylindrical feet in 5 longitudinal bands and scattered in the interambulacra ; dorsally the feet show some tendency to become papilliform. External and in- ternal anatomy typical of the genus. Spicules an outer layer of oval plates covered on the external side by a large reticulum; an inner layer of mostly regular 4-holed buttons with 10 marginal knobs and usually 2 central knobs; often the button is lozenge shaped with an accessoiy hole in each end. Feet with large end plate, reduced in some of the dorsal feet, and numerous large supporting tables with a huge reticu- lated spire; in some of the dorsal feet it covers almost the entire disk of the supporting table. Introvert with oblong tables with more or less com- pletely reduced 2-pillared spire, sometimes with a few teeth. Tentacles with knobbed plates or rods. Apparently rosettes are not present. Color bright orange-red dorsum and ends, ventrum pure white. (Color retained in alcohol.) Viviparous; the body cavity of the female contains often about half a dozen embryos of different developmental stages. Type.— M.C.Z. Type locality. — Monterey Bay. 116 ALLAN HANCOCK PACIFIC EXPEDITIONS VOL. 8 Distribution. — From Monterey Bay to Santa Cruz Islands, off Santa Barbara County, southern California. Specimens examined. — The type and numerous individuals, preserved as well as living, from Monterey to Santa Cruz Islands. Remarks. — Differs from the other 2 species in the color and the much heavier spicules. 2. Pachythyone lugubris (Deichmann) Plate 23, Figs. 7-9; text figure 6 Thy one lugubris Deichmann, 1939, p. 1, text figures 1-2. Diagnosis. — As for the genus. Color mottled brown. Spicules slightly smaller and more delicate than in P. rubra; tentacles without knobbed plates. Rosettes absent or rare. Viviparous. Holotype.— U.S.N. M. Type locality. — Magdalena Bay, west coast of L. Calif., 10-15 fms. Distribution. — Between Magdalena Bay and Cerros Island, west coast of L. Calif. Depth.— 10-40 fms. Specimens examined. — The types and the following specimens from the Velero Expeditions : 283-34. Thurloe Bay, L. Calif., 8-10 fms., off Thurloe Point, March 9, 1934, 5 specimens. 287-34. South Bay, Cerros Island, Mex., 10-15 fms., March 10, 1934, 12 specimens. Remarks. — The type, a female, contained 13 embiyos (collected in June). In the Hancock material collected earlier in the year no embryos were discovered. While the type material appeared to be devoid of rosettes in the ten- tacles, a few were found in the Hancock material which came from a much more northern locality. 3. Pachythyone pseudolugubris, new species Plate 22, Figs. 9-10; Plate 23, Figs. 1-6; text figure 6 Diagnosis. — Medium-sized form (up to 5 cm. long). Resembles lugubris in the external and inner anatomical features. Spicules an exter- nal layer of reticulated plates, an inner layer of regularly knobbed 4-holed buttons rarely elongate and with accessory holes in the ends. Feet with well-developed end plate; walls supported by numerous curved supporting tables with a low spire or none in the ventral feet; in the dorsal a number NO. 3 DEICHMANN : HOLOTHURIOIDEA ; PART I, DENDROCHIROTA 1 1 7 have a well-developed complex spire, although rarely as large as in lugubris. Introvert w^ith large tables with numerous holes and reduced spire. Tentacles exclusively with delicate rods or plates perforated by a large number of holes. Color mostly mottled brown, sometimes almost black ; occasionally a pale faded specimen may be encountered in the pre- served material. Type. — Holotype, AHF no. 34. Type locality. — Station 744-37, near Point Piaxtla, Sinaloa, Mex., Gulf of Calif., April 1, 1937, 6-8 fms. Distribution. — From the upper end of the Gulf of Calif, to the Gala- pagos. Depth. — From 6-25 fms. Specimens exarnined. — The type and paratypes and a number of indi- viduals secured at the following Velero stations: 145-34. North end of Albemarle Island, 6-7 fms., January 12, 1934, 1 specimen. 00 06 a o O 'OQQo 00^ I I I I I I M I I I I I I I I I I I I I Text fig. 6. Pachythyone lugubris (Deichmann). 1-2. Plate from tentacle and table from introvert. Pachythyone pseudolugubris, new species. 3-4. Plate from tentacle and table from introvert. Scale, ^00 mm. 118 ALLAN HANCOCK PACIFIC EXPEDITIONS VOL. 8 264-34. Petatlan Bay, Mex., 25 fms., March 2, 1934, 1 specimen. 683-37. Outside of Concepcion Bay, Max., March 15, 1937, 30 speci- mens. 744-37. Near Point Piaxtia, Sinaloa, Mex., Gulf of Calif., April 1, 1937, 7 specimens. Remarks. — The species resembles lugubris to an extraordinary degree, and future workers may decide that it merely represents a variety of that form. It is easily distinguished by the more simple supporting tables in the ventral feet, the shorter buttons which seem to lack all tendency to become lozenge shaped with accessory holes in the ends, and in the larger tables in the introvert and the absence of heavier rods and plates in the stem of the tentacles. The larger size and the darker color are, of course, quite useless characters, as lugubris possibly may be discovered to reach the same size and, although a dark color is common, paler individuals have been found. In no case have embryos been discovered, so presumably this species is not viviparous as are lugubris and rubra. The species has in some localities been found with the larger and paler Neothyone gibbosa, and the possibility has been considered that the latter represents senescent specimens of pseudolugubris, in which the ex- ternal layer of reticulated plates has been lost. The spicules seem, how- ever, to be definitely different. Pachythyone pseudolugubris shows little tendency to form handles, and the buttons have rarely more than 2 central knobs (except in the lozenge-shaped buttons), while Neothyone gibbosa normally forms handles, and as often as not the external handle has 3 knobs. Also the latter species shows definitely a tendency to develop large, smooth supporting plates in the ventral feet, while such plates are almost unknown in Pachythyone pseudolugubris, where the few supporting plates which lack a spire are narrow, thick, and in most cases knobbed. Genus 11. ATHYONE, new genus Diagnosis. — Medium-sized to large forms. Feet numerous, fairly stout. Tentacles large, bushy, the 2 ventral smaller. Skin soft, with few spicules. Calcareous ring stout with broad radials with distinct posterior prolongations and tall interradials with short anterior tooth. Spicules scattered swollen 4-holed buttons, often incomplete. Feet with loose-meshed end plate and numerous supporting rods, undoubtedly derived from tables. Introvert and tentacles with rosettes. Type species. — Athyone glasselli (Deichmann). NO. 3 DEICHIMANN : HOLOTHURIOIDEA ; PART I, DENDROCHIROTA 119 Remarks. — The diagnosis is based on the type of glasselli, a single adult individual. More material is needed, especially of younger individ- uals, to complete the diagnosis. The genus is not related to any other form known from the Panamic region. From the w^est coast of North America a form with somewhat similar spicules is known, Thyone benti Deich- mann, including a variety, var. zacae, from off Cerros Island, Lower Cal- ifornia, but that species has a taller, more delicate calcareous ring, exceedingly small tentacles, and larger spicules. Athyone glasselli (Deichmann) Thyone glasselli Deichmann, 1936, p. 63, text figure 1 ; 1937, p. 170, text figure 2. (Comparison with T. benti.) Diagnosis. — As for the genus. Color brownish. Resembles superficially Thyone briareus (Lesueur) from the coast of North America. Shallow- water form. Type.— M.C.Z., cat. no. 736. Type locality. — Punta Penasco, Sonora, Mexico. Distribution. — Known only from the type locality. Depth. — Shore, buried in sand. Specimens examined. — The type. Remarks. — The strongly contorted type specimen must have meas- ured more than 10 cm. in expanded, normal condition. More material is necessary to explain from what type of spicules the buttons and rods are derived. Very likely younger individuals may have distinct spire on the buttons and the supporting rods and thus be derived from tables. The species is not closely related to any other species known from the Panamic region. Thyone benti, from Puget Sound, and var. zacae from Cerros Island have similar spicules but much larger and definitely derived from tables; the calcareous ring is much more tubular and more delicate and the tentacles are unusually small. From the southern part of South America Thyone lechleri Lampert is known to have similar swollen but- tons, but the calcareous ring is entirely different with no posterior pro- longations at all. The only other soft-skinned Thyone with few spicules described from the Panamic region is the dubious Anaperus peruana Troschel, possibly identical with Lesson's species (see discussion, p. 120). Regarding Thyone ovulum Selenka, which Deichmann (1936, p. 65) mentioned as possibly the juvenile stage of A. peruana, the type has been re-examined and found to be a phyllophorid (see p. 125). 120 ALLAN HANCOCK PACIFIC EXPEDITIONS VOL. 8 Genus 12. ANAPERUS Troschel Anaperus Troschel (partim), 1846, p. 60. Diagnosis. — Large form with soft skin and numerous feet distributed without order. Tentacles 10, the 2 ventral smaller. Anus with calcareous teeth. Calcareous ring with posterior prolongations (apparently short) ; retractor muscles fleshy. Spicules not numerous except in the stem of the tentacles. Type species. — Anaperus peruviana (Lesson). Remarks. — ^As type species for this dubious genus Lesson's large den- drochirote species from Payta, Peru, has been chosen since it is a question whether Thyone briareus (Lesueur)from the western Atlantic belongs in the genus; Thyone fusus (O. F. Miiller) — the type species for Thyone s. str. — does definitely not belong here, and the fourth species, listed by Troschel as Thyone cigaro Troschel, from Labrador, cannot be identified. It is furthermore doubtful whether Lesson's and Troschel's species are identical. Very likely Lesson's species is a phyllophorid {Pattalus mollis (Selenka)), while Troschel's species is a soft-skinned Thyone which resembles T. briareus; ( Selenka actually united the 2 species after having examined Troschel's material in Berlin). The only other soft-skinned large Thyone known from the upper end of the Gulf of California is A thyone glasselli (Deichmann), which possibly may occur as far south as Peru. If we discount Troschel's state- ments about the color and size of his A. peruana — as they seem to be borrowed from Lesson's description — the assumption is not unreasonable. If re-examination of Troschel's material in Berlin should prove that that is the case, the name Athyone becomes a synonym of Anaperus; in that case Thyone briareus is excluded from the genus, and Troschel's species must be named Anaperus glasselli (Deichmann), syn. A. peruana Tro- schel, nee Holothuria peruviana Lesson. Another possibility is that Troschel's species is simply material of Thyone briareus which has been wrongly labeled. Such errors were by no means unusual in older times. Anaperus peruviana (Lesson) Holothuria peruviana Lesson, 1830, p. 124, pi. 46, fig. 1. Trepang peruana Jaeger, 1833, p. 25. — Brandt, 1835, p. 57. Anaperus peruanus Troschel, 1846, p. 61.— J. Miiller, 1854, pi. 9, fig. 9. NO. 3 DEICHMANN : HOLOTHURIOIDEA ; PART I, DENDROCHIROTA 121 Thyone peruana Selenka, 1867, p. 354. — Lampert, 1885, p. 160. — Sem- per, 1868, p. 242.— Theel, 1886, p. 140.— Deichmann, 1936, p. 65 (passim). Nee Jnaperus caroliniis Troschel, 1846, p. 62, nee Thyone tenella Selen- ka, 1867, p. 354, pi. 20, figs. 113-114. Referred to Thyone peru- ana by Selenka, 1868, p. 118 (both are synonyms of Thyone bri- ar eus and both came from the Atlantic coasts of North America). Diagnosis. — No diagnosis can be given, as Lesson and Troschel pos- sibly had two different species before them. Type. — Probably lost, or in Paris. Type locality. — Payta, Peru. Remarks. — Lesson's description and figure refer to an exceptionally large form, 6 inches long, with 8 bushy tentacles, numerous feet, and soft skin. The color of the animal was deep purplish. Troschel's numerous specimens in Berlin, likewise from Peru, refer apparently to a typical Thyone. They seem to resemble the West In- dian Thyone briareus Lesueur and have similar short posterior pro- longations on the radials and distinct anal teeth ; the 2 ventral tentacles are smaller (according to Troschel they were probably overlooked by Lesson, since he figured only 8). The calcareous spicules were not studied ; Troschel mentions merely that they were numerous in the stem of the tentacles. The size and color given by Troschel may very likely be quoted directly from Lesson. Selenka re-examined Troschel's material and decided that Anaperus carolinus Troschel and his own Thyone tenella from, respectively, Caro- lina and Texas were synonyms of the Peruvian form (both names are synonyms of Thyone briareus Lesueur, the common large Thyone from the eastern coasts of the United States). Lampert may possibly have examined some specimens of T. briareus and based his few remarks concerning Thyone peruana on a study of this material but not on the true Peruvian form; J. Miiller discusses (1854, p. 85) the stone canal and figures (p. 9), one from A. peruana, possibly from Troschel's material, but nothing of importance can be gleaned from his drawing. Whether Selenka for once was hasty in his identification or whether Troschel's material was mislabeled and actually represented material of Thyone briareus is impossible to decide. If the latter is true, it is obvious that the statements regarding the size and color came from Lesson's de- 122 ALLAN HANCOCK PACIFIC EXPEDITIONS VOL. 8 scription. So far, no species which resembles Thyone briareus is known from the Pacific coasts of America except A. glasselli. To solve the question it is necessary to re-examine Troschel's material in Berlin and possibly Lesson's type, if still extant. Very likely Lesson de- scribed Pattalus mollis, the only large purplish form, and overlooked some of the tentacles, while Troschel had either mislabeled material of Thyone briareus before him, an undescribed Thyone, or Athyone glas- selli. Family IL PhyllophoHdae Diagnosis. — Dendrochirota with more than 10 tentacles, the number ranging from 15 to 30. The tentacles either definitely of two sizes, large in the external circle, small in the inner, and appearing almost simultane- ously, or the sizes intergrade, the 2 circles being indistinctly set off from each other, and the full number is reached comparatively late in life. Feet restricted to the ambulacra, or scattered also in the interambulacra. Calcareous ring simple, or with distinct posterior prolongations; stone canal and Polian vesicle often in large numbers. Spicules of various kinds, mostly as tables, often reduced with age. Feet with end plate; walls with or without supporting tables or rods. Introvert with tables or plates, tentacles with or without spicules. The majority are shallow-water forms. Remarks. — A preliminary revision has been undertaken (Deichmann, 1938) which includes all the genera known from the American waters. To this list is now added Athyonidium, established for the species for- merly known as Thyone chilensis Semper. The latter is synonymous with Eucyclus duplicatus, new genus, new species, established by Lampert, 1885, pp. 290-292. Lampert was fully aware of the close similarity to Semper's species Thyone chilensis from Chile. Theel discussed the ques- tion; he believed the two species were identical but concluded that the number of tentacles possibly was more variable in the pohxhirote forms than generally known. Ludwig concurred in Theel's opinion and assumed that the tentacles were merely overlooked by Semper. He rejected, how- ever, the genus Eucyclus as superfluous and united it with Thyonidiurn under Phyllophorus. The Velero III has procured ample material of a form which unquestionably refers to the species which Semper examined. As in the case of Thyone ovulum Selenka — now Euthyonidium — in which Selenka overlooked the inner circle of smaller tentacles, so here the inner XO. 3 DEICHMANN: HOLOTHURIOIDEA ; PART I, DENDROCHIROTA 123 circle of smaller tentacles was completely missed by Semper and the spe- cies therefore likewise referred to Thyone.^ The genus resembles the northern genus Thyonidium but is distinguished by the almost completely resorbed interradials. As Eucyclus is preoccupied, a new genus had to be established. Key to the Genera of Phyllophoridae Known from the Panamic Region and Chilean Waters All the genera known from this region have at utmost 20 tentacles, and the feet are numerous in the interambulacra as in the genus Thyone. 1. Tentacles distinctly of 2 sizes, i.e., 10 large ones in the external circle and either 5 small ones, more or less deeply divided, or 5 small pairs of equal size in the inner circle 2 1 . Tentacles of varja'ng number and size, sometimes of almost the same size; the 2 circles are more or less confluent 3 2. Calcareous ring low, simple (or with insignificant posterior projections) ; interradials well developed, often pentagonal or heart-shaped — in many cases overlapping the radials. Spicules derived from 2- to 4-pillared tables, often reduced to plates with 2-4 knobs or spines indicating the pillars. Feet with end plate but no supporting tables, sometimes a few rods. Tentacles with rosettes and delicate rods. 1. Euthyonidium Deichmann p. 124 2. Calcareous ring low, simple; radials with long anterior tooth, interradials completely vestigial, easily overlooked. Spicules apparently lacking except for the end plate and a few branching rods 2. Athyonidium, new genus p. 127 3. Calcareous ring simple ; radials tall, posteriorly slightly incised ; interradials well developed. Spicules almost totally lacking, except for end plate and a few perforated plates. Tentacles 20, large, of almost equal size. Large reddish species 3. Pattalus Selenka p. 129 3. Calcareous ring with long posterior prolongations. Tentacles of different size, fairly delicate. Spicules 2- to 4-pillared tables sometimes scarce in older individuals. Small- to medium-sized forms 4. Phyllophorus Grube p. 132 6 In other specimens Semper noticed the inner circle of smaller tentacles and these he referred to Pattalus with a comment on the variability of the tentacles in this genus. 124 ALLAN HANCOCK PACIFIC EXPEDITIONS VOL. 8 Genus 1. EUTHYONIDIUM Deichmann Euthyonidiu?n Deichmann, 1938, p. 380. Diagnosis. — Medium-sized form (length 10 cm. or less). Tentacles definitely arranged as 10 large ones in 5 external pairs and 5 inner pairs (or 5 single ones?)'^ which are smaller. Apparently all the tentacles ap- pear at an early stage. Calcareous ring simple with tall rectangular radials, posteriorly with short protuberances which may be interpreted as rudi- mentary prolongations. Interradials well developed. Spicules small tables with oval to squarish disk, often with dentate or branching margin ; spire low, 2-4 pillared often reduced to knobs or spines or totally resorbed. Feet with large end plate and often a few small sup- porting rods, i-arely with trace of being derived from tables. Introvert with tables with numerous holes in the disk and spire often reduced. Tentacles with rosettes and delicate rods. Spicules often reduced with advancing age. Shallow-water forms, restricted to the tropical waters. Type species. — E. segiiroensis (Deichmann). Remarks. — From the West Indies 2 species are known, viz., the type species and E. occidentalis (Ludvvig). From the Panamic region 2 species are now known ; one represents the species which formerly was known as Thyone ovulum Selenka, and the other, which is new, is closely related to E. occidentalis from the West Indies. Key to the Species of Euthyonidium Known from the Panamic Region 1. Spicules oblong tables with dentate edge; spire 2 pillared, low, often reduced to knobs or spines, or lacking. Color grayish. . 2. Euthyonidium veleronis, new species 1. Spicules large tables with cross-shaped disk, often irregularly laciniatcd ; spire mostly reduced to a few knobs or spines. Color reddish brown. ... 1. Euthyonidium ovulum (Selenka) 1. Euthyonidium ovulum (Selenka) Plate 24, Figs. 1-7 Stolus ovulum Selenka, 1867, p. 356, pi. 20, fig. 117. — Semper, 1868, p. 66.— Lampert, 1885, p. 162.— Theel, 1886, p. 138. '^ The inner smaller pairs may possibly in some forms be found to be 5 smgle tentacles which are deeply divided as Heding (1936, p. 23) has found It to be the case in the type species of the closely related genus Thyonidium from the northern seas. NO. 3 DEICHMANN: HOLOTHURIOIDEA; PARTI, DENDROCHIROTA 125 Thy one ovuluin Deichmann, 1936, p. 64 (passim). Euthyonidiiim ovulum Deichmann, 1938, p. 380, text figure 12. Diagnosis. — Medium-sized form (probably about 10 cm. long) with soft, thick skin with numerous soft feet. Tentacles 10 large external ones and 10 inner ones which are much smaller and may be completely re- tracted into small pockets. Calcareous ring with radials posteriorly broad and deeply incised and tapering toward the anterior end; interradials unusually broad and heart shaped with a slight posterior incision, ante- riorly tapering to a point. Stone canals numerous and free, also several Polian vesicles. Inner anatomy otherwise normal. Spicules a scattered layer of tables with irregular disk varying from cross-shaped to a more or less branching or laciniated plate. Spire almost always reduced to a few spines. Feet with large end plate ; supporting rods are apparently totally lacking. Introvert seems to lack spicules; tentacles with few rosettes and delicate rods. Spicules more or less completely re- duced with advancing age and, except for the end plate, likely to be com- pletely overlooked. Type.— M.C.Z. Type locality. — Acapulco, Mexico. Distribution. — From Lower California to Peru. Specimens examined. — Selenka's type specimens (3) and several spec- imens from the Allan Hancock Expeditions : 261-34. Tangola Tangola, Mex., 1 fm., March 1, 1934, 1 specimen. 591-36. Port Escondido, L. Calif., Mex., shore, March 16. 1936, 40 specimens. 844-38. Lobos de Afuera Island, Peru, shore, February 14, 1938, 1 specimen. Remarks. — Re-examination of Selenka's type material of Stolus ovu- lum showed that Selenka had overlooked the inner circle of tentacles which were completely withdrawn into little pockets and that it was identical with various individuals collected by the Hancock Expeditions, and also by the Zaca. Euthyonidium ovulum has the same reddish-brown color which is extracted in alcohol as the much larger species Pattalus mollis Selenka from Peru and Chile. It would therefore be correct to consider whether the two forms are merely growth stages of the form which possibly ought to be called Pattalus peruana (Lesson) — see discussion under Pattalus and Anaperus. Deichmann (1936) considered ovulum as possibly being identical with Lesson's species (which was figured as having 8 tentacles) 126 ALLAN HANCOCK PACIFIC EXPEDITIONS VOL. 8 but was at that time unaware that ovulum was not a true Thyone. It would, however, be a hitherto unknown phenomenon that the smaller tentacles in the inner circle of a phyllophorid should be able to catch up in size with the large ones, and for that reason alone it would seem unlikely that ovulum could grow into Pattalus mollis usually with about 20 tentacles of almost identical size. Furthermore, the latter shows great variation in the number of tentacles, while ovulum invariably seems to acquire the full number at an early age. 2. Euthyonidium veleronis, new species Plate 24, Figs. 8-11 Diagnosis. — Medium-sized form, up to 10 cm. long; body tapering toward both ends with numerous soft feet scattered over the interambu- lacra; toward the oral and anal ends arranged in a more orderly manner along the ambulacra. Tentacles 5 large external pairs, and 5 inner smaller pairs closely appressed.^ Calcareous ring with 5, almost rectangular radi- als; posteriorly with short projections; interradials more or less heart shaped, with the point forward directed, and overlapping the radials. Stone canal single, attached in the dorsal mesentery ; Polian vesicles usu- ally 3 in number, muscle stomach delicate; intestine with normal course; retractors attached near the middle of the body where the 2 tufts of gonads are also attached. Spicules a scattered layer of small tables with oval to squarish disk with about 8 holes and dentate edge; spire low, mostly with 2 pillars, often reduced to knobs. Feet with large end plate and occasionally a few supporting rods. Introvert with tables ; tentacles with rosettes and small curved rods, mostly with perforated ends. Color mottled grayish. Type. — Holotype, AHF no. 35. Type locality. — Station 465-35, Playa Blanca, Costa Rica, shale beach between sand beach and rock reef, shore, February 8, 1935, 1 speci- men. Distribution. — The type locality. Depth. — Shore. Specimens examined. — The type. Remarks. — The species is closely related to E. occidentalis (Ludwig) known from the West Indies. 8 As only the type was available, the tentacles in the inner circle were not dis- sected out, but very likely this species has only 5 tentacles, deeply cleft, in the inner circle. NO. 3 DEICHMANN: H0L0THURI0IDEA;PARTI, DENDROCHIROTA 127 Genus 2. ATHYONIDIUM, new genus Eucyclus Lampert, 1885, p. 290.— Theel, 1886, p. 268.— Ludwig, 1887, p. 1239 (reprint p. 23). Name preoccupied. Diagnosis. — Large foiins (25 cm. or more) with thick, soft skin and numerous stout feet. Tentacles 5 large external pairs and 5 small inner pairs. Calcareous ring with 5 stout, almost rectangular radials and 5 in- significant interradials, often completely concealed in the tissue. One large dorsal stone canal, often branched and one or two tufts of smaller stone canals with minute heads. Numerous tufts of branched Polian vesicles. Inner anatomy seems otherwise quite typical of the family. Spicules large well-developed end plates, a few perforated spinous rods; tentacles with few rosettes in the younger individuals. Color gray- ish mottled to almost black, ventrum paler, tentacles dark. Shallow-water forms. Type species. — Athyonidimn chilensis (Semper). Remarks. — The genus is monotypic and related to Thyonidium and Euthyonidium, but the strikingly reduced interradials give it a position almost unique among the Phyllophoridae. Very little can be said about the spicules, as they are reduced even in small individuals (5 cm. long). They may be present in still younger specimens, and one would expect them to be tables, possibly with the spire reduced. Athyonidium chilensis (Semper) Thy one (Stolus) chilensis Semper, 1868, p. 241, pi. 40, figs. 3-6. — Lam- pert, 1885, p. 156.— Theel, 1886, p. 139. Eucyclus duplicatus Lampert, 1885, p. 250.— Theel, 1886, p. 268. Diagnosis. — As for the genus. Type. — Possibly in Germany. Type locality. — Coast of Chile. Distribution. — From Chile to Ancon, Peru. Depth. — Shallow water, at tidemark, in sand. Specimens examined. — The following material from the Allan Han- cock Expeditions: 828-38. San Juan Bay, Peru, shore, February 8, 1938, numerous speci- mens. 831-38. Independencia Bay, Peru, shore, February 9, 1938, 3 specimens. Also the following specimens in the IVLC.Z. : 21 from Talcahuana, Chile; 3 thrown up on the beach in Ancon, Peru, with Pattalus mollis. 128 ALLAN HANCOCK PACIFIC EXPEDITIONS VOL.8 Remarks. — I have ventured to transfer Semper's Tkyone chilcnsis to this genus, as his description of that unusual form agrees exactly with the numerous specimens I have had occasion to examine, and the species differs distinctly from Pattalus mollis Selenka, of which I have likewise had the opportunity to study a long series. My results are in complete agreement with Ludwig's conclusions, that Lampert's species is a syno- nym of Semper's Thy one chilensis (and probably some or all of his Pattalus mollis). But contrary to Semper's and Theel's belief, the num- ber of tentacles is constant in this species. The inner circle of tentacles is often completely withdrawn so that only the 10 larger ones are visible. The inner tentacles become quite stout with advancing age but remain, nevertheless, always distinctly smaller than the external ones, and the inner circle is well separated from the outer one. The radials, as Semper describes them, are slipper shaped, al- most rectangular, broadest posteriorly with a large depression below the attachment for the retractors ; the interradials are small in the young indi- viduals; in the older they are completely concealed in the thick tissue, and the calcareous ring appears to be composed of 5 stout radials. Semper noticed only one tuft of small accessory stone canals but may possibly have failed to examine both sides of the mesentery. The Polian vesicles are distinctly arranged in tufts, and most of them are branched. Except for the presence of end plate and a few rosettes in the tentacles, spicules are so rare that they often are difficult to find. Semper figures a few branching rods perforated by a few holes, and such spicules have been found. The color is strikingly different from that of Pattalus mollis even in preserved individuals. It is mottled gray, sometimes almost black on the dorsal side, with paler ventral side and black tentacles. In freshly col- lected individuals the tube feet may have a reddish tinge, possibly caused by the hemoglobin contained in the water vascular sj^stem. The skin seems never to contain a reddish pigment as Pattalus mollis, nor does it ever fade to that uniform dull reddish brown which is so characteristic of Selenka's species. Athyonidium chilensis seems to be the most common phyllophorid known from Chile. On the coast of Peru it is often known to occur in the same localities as Pattalus mollis, but buried in sand with the tentacle crown expanded on the surface, while the former clings to the rocks (H. L. Clark's observations). NO. 3 DEICHMANN : HOLOTHURIOIDEA ; PART I, DENDROCHIROTA 129 The Velero material measures from 5 to 20 cm. ; the largest individu- als in the M.C.Z. measure more than 25 cm. in length. The occurrence of this typical Chilean species in Peruvian waters makes it impossible to decide whether this species or Pat talus mollis rep- resents Lesson's troublesome form, Holothuria peruana. Possibly a care- ful survey at Payta, the type locality for peruana, may show that only one of the 2 species occurs there. Pattalus mollis Selenka does occur in Payta (material in the M.C.Z. ), but A. chilensis also may possibly be found there, for both species are known to occur in the same localities, i.e., at Ancon, Peru, and at Station 828-38. Genus 3. PATTALUS Selenka Pattalus Selenka, 1868, p. 113. Diagnosis. — Large form (20 cm. or more) with up to 20 large tenta- cles of almost equal size. Skin thick with numerous tube feet. Calcareous ring with 5 tall rectangular radials, with posterior corners rounded into low protuberances; interradials with broad low basal part and a long anterior tooth, often concealed in the thick tissue. Dorsally a long stone canal with small head; Polian vesicles numerous, hanging as a fringe around the ring canal, a few are dichotomously divided. Other anatomical features typical of the family. Spicules a few branched rods, feet with large end plate. Color reddish brown with a pigment which is dissolved in alcohol ; specimens which have been preserved in alcohol for a long time are uniformly dull brown. Shal- low water. Type species. — Pattalus mollis Selenka. Remarks. — The genus is monotypic and seems not related to any other form. It has in the course of time been confused with Athyonidium chil- ensis (Semper) but is definitely different from that species. It may pos- sibly be identical with Euthyonidium ovulum (Selenka), although it seems impossible that the smaller inner tentacles should ever be able to attain the size of those in the external circle. The 2 species have the same reddish color with pigment which is extracted in alcohol. They differ as far as our present material shows in the more heart-shaped interradials in E. ovulum, with a short anterior tooth, while P. mollis has a remarkably long anterior tooth on the interradials. Also E. ovulum seems to lack a large, dorsally attached, stone canal which is so characteristic a feature in P. mollis. The large P. mollis is extremely common in Peru and is also 130 ALLAN HANCOCK PACIFIC EXPEDITIONS VOL.8 known from Concha, Chile, while the smaller E. ovulum is known from various localities in the Panamic region and has once been reported from Lobos de Afuera Island, Peru (see above, p. 125). (The M.C.Z. has fur- ther two lots marked "locality dubious" from, respectivelj^, Hawaii, and Mazatlan, Mexico.) If P attains mollis is assumed to represent the full- grown stage of Euthyonidium ovulum, it is impossible to explain how that large species could have escaped discovery in the Panamic region. (See also under E. ovulum.) Pattalus mollis Selenka Pattalus mollis Selenka, 1868, p. 113, pi. 8, figs. 4-5. Thyonidium peruanum Semper, 1868, p. 67, pi. 15, fig. 17. Thyonidium molle Semper, 1868, p. 243.— Ludwig, 1874, p. 4; 1883, p. 163; 1887, p. 25.— Lampert, 1885, p. 174 (partim).—^\\kt\, 1886, p. 144. Anaperus peruana Verrill, 1867, p. 322. Pattalus peruana Verrill, 1867, p. 376. Phyllophorus peruvianus H. L. Clark, 1910, p. 351 (partim). Diagnosis. — As for the genus. Color reddish purplish, pigment ex- tracted in alcohol ; preserved specimens usually dull brown. Type. — Berlin. Type locality. — Peru and Chile. Distribution. — Common in Chile and Peru. Depth. — Shallow water, to 25 fms., often collected at tidemark, cling- ing to rocks (H. L. Clark). Specimens examined. — A large series in U.S.N.M. and M.C.Z. Also several specimens from the Allan Hancock Expeditions : 375-35. Independencia Bay, Peru, shore, January 13, 1935, 13 speci- mens. 391-35. Lobos de Afuera Island, shore, January 17, 1935, 8 specimens. 820-38. San Nicholas Bay, Peru, 10-25 fms., Februaiy 6, 1938, 4 speci- mens. 828-38. San Juan Bay, Peru, shore, February 8, 1938, 9 specimens. 831-38. Independencia Bay, Peru, shore, February 9, 1938, 3 specimens. 837-38. North Chincha Island, Peru, shore, February 11, 1938, 6 speci- mens. 844-38. Lobos de Afuera Island, Peru, shore, February 14, 1938, 2 specimens. NO. 3 DEICHMANN: HOLOTHURIOIDEA ; PART I, DEXDROCHIROTA 131 Remarks. — The species seems to be the most characteristic holothurian from the coasts of Peru and certain localities in Chile. In some cases it occurs in the same localities as Athyoniditim chilensis, but the 2 species have an entirelj^ different ecology. Pattalus mollis is found completely exposed, clinging to rocks, while Athyonidium chilensis is found buried in sand with its tentacles extending flatly on the surface (H. L. Clark, observed on the Hancock Expeditions in the spring of 1938). In pre- served condition the 2 species are entirely unlike except in size; P. mollis is uniformly purplish red or faded brown, while the other species is mot- tled gray, sometimes with almost black dorsum, black tentacles, and more lightly colored ventrum. Internally P. mollis has large well-developed interradials with long anterior tooth, while Athyonidium chilensis has broad radials and the interradials are almost completely resorbed or hid- den in the leathery tissue. It would be tempting to select Lesson's name peruanus for this species so typical of Peru, especially since material in the M.C.Z. shows that Pattalus mollis does occur in Payta, Peru, the type locality for Lesson's species. But there is still the possibility that Lesson did have a true deka- chirote form before him, with 2 smaller ventral tentacles which were overlooked, a form which has not as yet been rediscovered except possibly by Troschel. Furthermore, both P. mollis and A. chilensis often occur in the same localities, and Lesson's description and figures may refer to a composite species, the low number of tentacles — although incorrect — being taken from A. chilensis, while the color note "rouge violet eclatant et fonce" refers to P. mollis. No other species has caused so much confusion in the literature as this species (including A. chilensis). It has usually been identified with Les- son's Holothuria peruana, although, if Troschel is correct, the latter is one of the members of the genus Thyone s.l. Semper obviously referred some of his material of A. chilensis — those in which he observed the 10 inner small tentacles — to this species and commented on the variability of the number and size of the tentacles in this genus; Lampert did the same, as also H. L. Clark. Verrill referred his material of mollis to Anaperus peruanus Troschel but realized the discrepancy in the number of tentacles and corrected the name to "Pattalus peruanus — closely related to Selenka's P. mollis," without indicating wherein the 2 species differed. The reasons why P. mollis cannot represent the mature stage of Euthyonidium ovulum Selenka are mentioned above (under that species). 132 ALLAN HANCOCK PACIFIC EXPEDITIONS VOL. 8 Genus 4. PHYLLOPHORUS Grube, 1840 Phyllophorus Auctores. Nee Phyllophorus Heding, 1936 (Thyonidium Diiben & Koren). Thyonidium Auctores. Nee Thyonidium Diiben & Koren, 1844, p. 303. Diagnosis. — Medium-sized forms (6-15 cm.) with feet distributed in the interambulacra. Tentacles up to 20 in number, of varying size, not sharply set off into 2 circles ; the complete number is reached late in the animal's life. Calcareous ring with distinct posterior prolongations on the radials ; interradials well developed, of varying shape ; ring often com- posed of smaller pieces, mosaiclike. Spicules 2- to 4-pillared tables, spire usually retained. Feet with large end plate ; walls with or without supporting tables, or a few rods. Intro- vert usually with tables with low spire and numerous perforations in the disk; tentacles with either perforated plates or delicate rods; rosettes seem normally to be present in the introvert and tentacles. Shallow-water forms, tropical and subtropical. Type species. — Phyllophorus urna Grube. Remarks. — The type species is common in the Mediterranean Sea. Grube's description and figures are not particularly convincing, but an excellent account is given by Sars (1846). Unfortunately it is written in the Norwegian language and is therefore not so well known as it deserves. A number of tropical species belong to this genus. (See Engel, 1933, and Deichmann, 1930 and 1938.) From American waters 5 species are reported from the West Indies and coast of Brazil. From the tropical west coast of America 2 species are known. One was described by Ludwig in 1894, the other by Deich- mann in 1938. The latter species is closely related to one of the West Indian forms, while that of Ludwig seems completely unrelated to all other members of the genus. No true Phyllophorus is known from the west coast of North America, or from Chile or Hawaii. Key to the Species of Phyllophorus Known from the Panamic Region 1. Spicules tables with oval disk with an average of 8 marginal holes; spire distinctly 4 pillared, usually with a single cross- beam and ending in a large number of spines. Feet with large end plate and numerous supporting tables with broad elongate disk with numerous holes and a huge spire ending in a conical NO, 3 deichmann: holothurioidea; part i, dendrochirota 133 tooth which often pierces the skin 1. Phyllophorus aculeatus Ludwig 1. Spicules tables with oval disk with 4 large and 4 smaller holes, the latter often wedge shaped ; spire usually with 2 pillars and ending in 2 tufts of few spines, sometimes ending in 4 spines. Feet with large end plate and a few supporting tables with broad elongate disk with numerous holes and comparatively low spire with a single crossbeam and ending in 2 diverging spines or horns, rarely in a single point 2. Phyllophorus zacae Deichmann 1. Phyllophorus aculeatus Ludwig Plate 25, Figs. 1-8 Phyllophorus aculeatus Ludwig, 1894, p. 128, pi. 13, figs. 6-11. — Deich- mann, 1938, p. 381 (passim). Diagnosis. — Medium-sized form (type measured 6.5 cm. but was strongly contracted). Feet numerous, scattered almost uniformly over the body. Tentacles of varjn'ng size, up to 20 in number. Calcareous ring with long posterior prolongations on the radials ; interradials with heart- shaped to almost rhomboid base and long anterior tooth; the basal part overlaps the radials. Spicules numerous tables with oval disk with a varying number of marginal holes, usually 8 ; spire mostly with 4 pillars, a single crossbeam, and a wreath of small spines on the top. Feet with large end plate and heavy supporting tables with broad oval disk with numerous holes and an enormous spire which tapers into a conical tooth. Introvert with tables with oval, lacelike disk and spire composed of 2 to 4 pillars. Tentacles with a few rosettes and numerous delicate rods, rarely with the ends per- forated. Color grayish with purplish tentacles. T>^/.e.— U.S.N.M. Type locality. — Gulf of Panama, shore. Distribution. — Known from the type locality only. Depth. — Shallow water. Specimens examined. — The type, the only specimen known in exist- ence in any collection. Remarks. — The strongly contracted type measured probably more than 10 cm. in length in expanded condition. The inner organs are strong- ly distorted, and very little can be said about them. The gonads are well developed, forming long tubes, dichotomously divided near the base. 134 ALLAN HANCOCK PACIFIC EXPEDITIOXS VOL.8 The spicules show some similarity to those characteristic of Thyone strangeri (see pi. 19), and for a while I thought that Ludwig had made a mistake In counting the tentacles. Re-examination of the type and com- parison of the spicules showed beyond doubt that Ludwig was right and that the 2 species cannot possibly be confused as a glance at the figures of the spicules will show. It Is remarkable that this well-defined species has never been taken again, especially since the type localit}^ is one of the most frequently vis- ited collecting grounds in the Panamic waters. 2. Phyllophorus zacae Delchmann Plate 24, Figs. 12-21 Phyllophorus zacae Delchmann, 1938, p. 381. Diagnosis. — Medium-sized form, feet numerous scattered almost uni- formly over the body, not crowded. Tentacles 15-20 In number, long, delicate, of varying size. Calcareous ring with well-developed posterior prolongations on the radials ; the anterior tooth Is long rectangular with a constriction at Its base; the interradlals are more or less heart shaped with a broad base, overlapping the radials and with a short tooth. Spicules delicate tables with oval disk with 4 larger and 4 smaller holes, the latter often wedge shaped; spire with 2 to 4 pillars, a single crossbeam, and ending in 4 tufts of few spines, sometimes reduced to 4 undivided spines. Feet with large end plate and a few supporting tables with broad oblong disk with numerous holes ; spire low or moderately high with one crossbeam, and usually ending in 2 diverging spines or horns or in a single point. Introvert with delicate tables; tentacles with delicate rods and rosettes. Color reddish to white. Type.— M.C.Z. Type locality. — Tangola Tangola Bay, Mex. Distribution. — Ranging from L. Calif, to the Galapagos. Depth. — ^The type came from 10 fms. depth. Specimens exa?nined. — The type, and 4 individuals from the follow- ing Velero III stations : 190-34. Galapagos, Lat. 0° 55' S. ; Long. 90° 30' W., 58-60 fms., Jan- uary 26, 1934, 2 young. 517-36. East side of San Francisco Island, Gulf of Calif., 15 fms., Feb- ruary 25, 1936, 1 specimen, oral end missing. 816-38. North of Hood Island, Galapagos, 50-100 fms., January 29, 1938, 1 specimen. NO. 3 DEICHMANN : HOLOTHURIOIDEA ; PART I, DENDROCHIROTA 135 Remarks. — The species is closely related to Phyllophorus destichadus Deichmann from the West Indian waters. It differs in the presence of supporting tables in the feet and in minor details of the calcareous ring and the spicules. A species with somewhat similar spicules was described from Hawaii by Fisher, 1907, and is now referred to Neothyonidium (Deichmann, 1938, p. 382). The Hawaiian species has tentacles in 2 separate circles and of 2 different sizes, and the calcareous ring is of another type, with long narrow interradials which are firmly joined to the radials, not over- lapping them. Family III. Psolidae Diagnosis. — Dendrochirota with part of the ventral side developed as a thin-walled sole, with feet along the margin and in many forms also along the odd ambulacrum of the sole. Dorsal side (including the oral and anal ends) covered more or less completely by scales; in certain genera some scales are perforated for the passage of tube feet; in one genus no feet are developed on the dorsal side. Tentacles 10 (15 in one genus), the 2 ventral ones are often smaller; in the few deep water forms the tentacles are almost finger shaped, with few or no branches. Cal- careous ring simple; retractors of unequal length; gonads in 2 tufts on the dorsal side opening on a papilla behind the tentacles. Spicules in sole, perforated plates or buttons, smooth or knobbed ; in some forms the external deposits may be cup shaped, in others gradually transformed into reticulated bodies ; in certain species the spicules become scarce with age. Feet with end plate and a varying number of supporting rods or plates. Dorsal side with or without a layer of spicules outside the scales, as grains, cups, hourglass-shaped bodies, plates, etc. Dorsal ap- pendages, if present, with or without end plate and supporting rods or plates. Tentacles with or without perforated plates or rods; sometimes the spicules disappear in older individuals; a few forms have rosettes. Remarks. — The family comprises about half a dozen genera and represents a rather interesting series of evolutionary steps. Of the 3 genera which are known from the Panamic waters Thyonepsolus represents un- doubtedly the most primitive group, indistinctly separated from Psolid- ium, while the highest evolutionar>' stage is represented by the genus Psolus. The inner anatomy of the 3 genera is very similar. The most striking difference is that in the 2 first-named genera the third loop of the 136 ALLAN HANCOCK PACIFIC EXPEDITIONS VOL.8 intestine is attached in the left ventral interambulacrum, while in the last genus it is attached in the right interambulacrum. This may indicate that the Thyonepsolus-Psolidiurn series represents an independent branch and the Psolus series another, or it may simply be that the mesenterial attachment has shifted completely over in the most advanced genus. Some of the members of the genus Psolidium have very few dorsal feet, and these have formerly partly been referred to the genus Psolus. Key to the Genera of the Family Psolidae Known from the Panamic Region 1. Dorsal side (including oral and anal ends) without appendages (except the anal papillae and in some forms a few abortive feet on the introvert) 3. Psolus Oken p. 146 1. Dorsal side with a varying number of tube feet, usually perfor- ating the scales 2 2. Dorsal side characterized by the presence of large hourglass- shaped bodies. Tube feet on dorsal side with walls stiffened by numerous curved squarish or circular plates, sometimes reduced to crosses (also a few oblong supporting plates may be pres- ent) ; towerlike deposits present in most species, often reduced with age 1. Thyonepsolus H. L. Clark p. 136 2. Dorsal side without large hourglass-shaped bodies, at utmost small cups or baskets. Dorsal tube feet in some forms supported by squarish plates, in others by oblong plates or rods, in others superficial deposits seem to be entirely lacking on the dorsum; towerlike deposits sometimes present. 2. Psolidium Ludwig p. 141 Genus 1. THYONEPSOLUS H. L. Clark, 1901 Thyonepsolus H. L. Clark, 1901, p. 169.— Deichmann, 1930, p. 192; 1937, p. 172. Psolidium Ludwig, 1904, p. 689. Lissothuria Verrill, 1867, p. 322. Diagnosis. — Small to medium-sized forms with 10 tentacles, the 2 ventral smaller; sole sharply set off; feet numerous in 3 crowded bands. Dorsal scales few to numerous, covering the back more or less completely ; feet numerous or few; a well-developed external layer of spicules covers the scales. NO. 3 deichmann: holothurioidea; parti, dendrochirota 137 Spicules in sole perforated plates, knobbed or smooth, some may form shallow baskets; feet with end plate and perforated supporting rods or plates. Dorsal side with a varja'ng number of large towerlike deposits, reduced with age, in some species shorter, approaching the shape of grains; also hourglass-shaped bodies and curved plates. Feet with a small end plate or none, and the walls supported by curved squarish plates, some- times reduced to crosses and rods. Tentacles with heavy perforated plates and smaller plates and rods, in some species rosettes. Shallow-water forms. Type species. — Thyonepsolus nutriens H. L. Clark. Remarks. — The genus seems to be restricted to the American waters. The type species is known from Monterey Bay, California, and south- ward to Santa Cruz Islands ; another species is known from the West Indian seas, while 3 occur in the Panamic region and adjacent waters. Two of these are here described as new. The type species is known to be viviparous; the life histories of the other species are yet unknown. Key to the Species of Thyonepsolus Known from the Panamic Region and the Californian Waters 1. Dorsal scale covering incomplete in the midline (in the adult individuals). Scales numerous and small; dorsal feet numer- ous; external layer of spicules well developed. Sole with large perforated plates and an outer layer of flattened baskets. Per- forated plates in tentacles decreasing in size, no rosettes. Vivip- arous; carries its large eggs in pits on the back. Californian waters (and Galapagos?) 1. Thyonepsolus nutriens H. L. Clark 1. Dorsal scale covering complete in the midline. Dorsal feet not remarkably numerous ; external layer of spicules not remark- ably crowded, varyingly developed. Sole without external layer of flattened baskets. Panamic waters 2 2. Tentacles with rosettes and delicate rods besides heavy narrow rods; plates in sole with indented margin. Midventral band with feet crowded. . . 2. Thyonepsolus beebei Deichmann 2. Tentacles without rosettes and delicate rods, only heavy plates. Midventral band of feet with few feet 3 3. Dorsal side with few (7-8) scales and fairly numerous feet. Hourglass-shaped bodies large, irregular. Sole with knobbed plates. (Towers were not found in the type.) 3. Thyonepsolus veleronis, new species 138 ALLAN HANCOCK PACIFIC EXPEDITIONS VOL.8 3. Dorsal side with numerous scales (14 between oral and anal scales) but comparatively few feet, easily overlooked. Dorsal side with typical hourglasses of lacelike structure and large towers which in older individuals become shortened, so that they are thimble shaped. Sole with 4-holed buttons and plates with marginal knobs ; holes comparatively small 4. Thyonepsolus hancocki, new species 1. Thyonepsolus nutriens H. L. Clark Plate 26, Figs. 1-5 Thyonepsolus nutriens H. L. Clark, 1901, p. 169; 1901a, p. 491, text figures. — Deichmann, 1930, p. 193 (passim); 1937, p. 174. Psolidium nutriens Ludwig, 1904, p. 689. Diagnosis. — Small form (length of sole 2 cm.) ; distinct sole with numerous feet in 3 crowded bands. Dorsal side with numerous small scales, lacking in the midline (except in very young individuals), feet numerous, and external layer of spicules well developed. Spicules in sole perforated plates (0.10-0.15 mm.) and smaller flattened baskets (0.06 mm.) ; feet with end plate and supporting rods. Dorsal side with scales and perforated plates (0.18 mm.) often slightly concave, and hourglass- shaped bodies (0.10 mm.). In most individuals a number of huge tower- like deposits (0.20-0.30 mm.) numerous in young individuals where the other types of external spicules may be scarce. Dorsal feet with rudimen- tary end plate and curved perforated plates or rods in the walls. Introvert and tentacles with perforated plates or buttons and rods. Type.— M.C.Z. Type locality. — Pacific Grove, California, in tide pools. Distribution. — From the type locality southward, Santa Cruz Islands, off Santa Barbara, California. Depth. — Tide pools to few fms. depth. Specimens examined. — The type and about 50 from various localities. The following material examined from the Allan Hancock Expedi- tions : 11-32. Conway Bay, Indefatigable Island, Galapagos, shore, January 12, 1932, 1 specimen. Remarks. — A single specimen in the Allan Hancock Expeditions has been identified with this species, but the label says Station 1 1-32 ( ?) which is Conway Bay, Indefatigable Island, Galapagos, shore. NO, 3 DEICHMANN: HOLOTHURIOIDEA ; PART I, DENDROCHIROTA 139 As this discontinued distribution seems at most unbelievable, it is for the present assumed that the labeling is erroneous. The record is given here in case future investigation should prove that it is correct and a species closely related to T. nutriens, or identical with it, does occur in the waters around Galapagos Islands. Comparison with material from California has failed to reveal any tangible differences in the spicules. The living animal (observed in Hopkins Marine Station) is brilliant red with a more pinkish sole. The inner anatomy is similar to that of Psoltdiurn. The third mesentery is attached in the left ventral interambu- lacrum, close to the midventral ambulacrum. The respiratory trees are feebly branched and attached to the lateral interambulacra; the muscula- ture is moderately developed, the retractors short and attached near the oral end. The genital organs form short tubes in 2 tufts near the oral end ; they open on a papilla immediately behind the tentacles ; small gen- ital organs are present in specimens 0.6 mm. long. The eggs are huge, about 1 mm. in diameter, and reddish gray, opaque. The eggs are trans- ferred to the back of the female and lodged in pits; about 10 eggs are hatched at a time; when ready to leave the mother in a few weeks, the young are pale rose colored and have their full number of tentacles and 6 large tube feet. Specimens 2 mm. long have developed a distinct sole; those 5 mm. long have 3 rows of feet on the ventral sole. In Monterey Bay the female has been observed brooding its eggs from March to No- vember; very likely it broods during the remaining winter months also. 2. Thyonepsolus beebei Deichmann Plate 28, Figs. 1-3 Thyonepsolus beebei Deichmann, 1937, p. 172, text figure 3, 1-10; 1938, p. 382. Diagnosis. — Small form (length of sole few cm.). Exterior typical of the genus ; dorsal side completely covered by scales. Ventral sole with flat plates with scalloped edge ; dorsal side with large complicated lacelike hourglass-shaped bodies, towers and curved perforated plates; tube feet with end plate and curved plates with 4 central holes and numerous mar- ginal ones. Tentacles with heavy rods in stem ; branches with delicate rods and rosettes. Type.— M.C.Z. Type locality. — Off Arena Bank, L. Calif., 2.5 fms. Distribution. — West coast of Lower Calif., Mex., Costa Rica, pos- sibly also Panama ( ?Lissothuria ornata Verrill, 1867, p. 322). 140 ALLAN HANCOCK PACIFIC EXPEDITIONS VOL. 8 Specimens examined. — From the following stations: 261-34. Tangola Tangola, Mexico, 15-20 fms., March 1, 1934, 1 specimen. 283-34. Thurloe Bay, West Coast of L. Calif., 8-10 fms., March 9, 1934, 3 specimens. 3. Thyonepsolus veleronis, new species Plate 26, Figs. 6-8 ; Plate 27, Figs. 8-9 Diagnosis. — Small form (type less than 2 cm. long) ; distinct sole with feet in a double row along the edge and in a scattered row along the midventral ambulacrum; dorsal side with comparatively few large scales and relatively numerous feet ; external layer of spicules well developed. Spicules in sole knobbed plates ; dorsally huge irregular hourglass-shaped bodies, more cup shaped and less lacelike than in the other species. (Tow- ers were not observed in the type.) Dorsal feet apparently without end plate, walls supported by squarish curved plates of the typical structure. Tentacles with heavy plates and rods with small holes; branches with delicate rods or plates ; apparently no rosettes. Type. — Holotype, AHF no. 36. Type locality. — Station 147-34, Tagus Cove, Albemarle Island, Ga- lapagos, dredging south of Cove, 30 fms., January 13, 1934. Distribution. — Type locality. Depth. — Dredged from 30 fms. Specimens examined. — The type. Remarks. — The single individual measures 1.8 cm. in length (some- what distorted). Its exterior and its spicules are very characteristic, and it cannot be confused with any of the other species of Thyonepsolus. The lack of towerlike deposits may be accidental — it is not uncommon in older individuals of Thyonepsolus nutriens. It is a question whether this species properly belongs in Thyonepsolus or Psolidium, but the large hourglass-shaped spicules are so much more reminiscent of those characteristic of Thyonepsolus than of the small cups which are found in Psolidium that I have preferred at present, at least, to refer it to the former genus. 4. Thyonepsolus hancocki, new species Plate 27, Figs. 1-7 Diagnosis.- — Comparatively large form (sole up to 4 cm. long) ; sole sharply set off; feet in a double row along the edge and in a scattered NO. 3 DEICHMANN : HOLOTHURIOIDEA ; PART I, DENDROCHIROTA 141 band along the midventral ambulacrum. Dorsal side with numerous im- bricating scales, about 14 between oral and anal apertures in the largest individual. Dorsal feet few, rudimentary, easily overlooked. Spicules in sole var^^ing from 4-holed buttons to irregular, perforated plates with marginal knobs and occasionally a few knobs near the center. Feet with end plate and perforated rods and plates. Dorsal side with scales, delicate hourglass-shaped cups of lacelike structure and huge tow- ers which in the older individuals are partly resorbed from the tip, so that they become shorter, thimblelike. Feet apparently without end plate; walls supported by cui-ved squarish plates with 4 central holes and a varj^- ing number of smaller marginal ones. Tentacles with heavy plates and rods ; in the branches delicate plates and rods ; apparently no rosettes. Type. — Holotype, AHF no. 37, 19 paratypes. Type locality. — Station 521-36, Agua Verde Bay, L. Calif., north of anchorage, 5-10 fms., February 27, 1936. Distribution. — Gulf of Calif, to Ecuador. Depth. — From 5-165 fms. Specimens examined. — The following individuals from the Allan Hancock Expeditions: 213-34. La Plata Island, Ecuador, dredging north of anchorage, rocky, 7-10 fms., February 10, 1934, 3 small specimens. 521-36. Agua Verde Bay, L. Calif., Mex., 5-10 fms., February 27, 1936, 5 small specimens. 529-36. Off San Francisquito Bay, L. Calif., Mex., 165 fms., March 1, 1936, 12 large specimens. 854-38. Gorgona Island, Colombia, north of Island, 40-60 fms., Febru- ary 24, 1938, 7 large and 2 small specimens. Remarks. — A well-defined species which is easily recognized. Genus 2. PSOLIDIUM Ludwig, 1887 Diagnosis. — Small forms (sole few cm. long) ; sole sharply set off; with feet along the edges and few or many in the midventral ambulacrum ; dorsal side with numerous imbricating scales, and a vaiying number of tube feet which pass out through some of the scales. Spicules in sole plates or buttons, smooth to knobbed, usually also an external layer of small deep cups. Feet with end plate and supporting plates or rods. Dorsal side usually with an external layer of cups (possibly lacking in some species) ; besides grain or towers (more or less completely reduced with 142 ALLAN HANCOCK PACIFIC EXPEDITIONS VOL. 8 age). Dorsal tube feet with or without end plate and supporting rods or plates in the walls ( the type species has squarish plates of similar type as those in Thyonepsolus). Type species. — Psolidium dorsipes Ludwig. Remarks. — The genus comprises a number of species. A few of these have formerly been referred to Psolus because the few dorsal tube feet were overlooked. On the other hand, it seems as if Psolidium convergens Herouard (1901, p. XXX) ought to be transferred to some other genus, judging from the description given by Perrier ( 1905, p. 38, pi. 2, figs. 2-4, text figures D-F). The genus is closely related to Thyonepsolus H. L. Clark; actually Ludwig considered (1904) the latter as a synonym of Psolidium. The similarities between the 2 genera are even greater than assumed since it has been discovered that the curved plates in the type species are partly supporting plates for the dorsal tube feet and likewise that the character- istic towers also may be present (see below). Nevertheless, it seems justi- fiable for the present to retain the 2 genera on account of the more com- plex hourglass-shaped bodies which are typical in ThyonepsoluSj while Psolidium has small cups or baskets. Four species are discussed here, all represented in the Allan Hancock collections and all taken at moderate depth or even in shallow water. One is the type species, while 3 are described as new. Key to the Species of Psolidium Known from the Panamic Region and Adjacent Waters 1. Tube feet fairly numerous in the midventral ambulacrum, also numerous on the dorsal side where the scales are small and nu- merous. Sole with plates with fairly large holes, smooth or knobbed, and deeply convex cups. Dorsal side with numerous deep cups and often also towerlike deposits; tube feet with numerous curved squarish supporting plates, a few are narrow, rod shaped 1. Psolidium dorsipes Ludwig 1. Tube feet in midventral ambulacrum few. Dorsal feet easily overlooked. 2 2. Dorsal scales with a varying number of prominent pearllike projections. Spicules in sole 4-holed buttons or plates with knobbed surface and varying from delicate to stout. Oral opening with large triangular scales; many small scales inter- NO. 3 DEICHMANN: HOLOTHURIOIDEA ; PART I, DEXDROCHIROTA 143 calated between the larger scales 3. Psolidium ekmani, new species 2. Dorsal scales smooth, without pearllike projections 3 3. Dorsal side covered by numerous thimble-shaped grains with flat base (reduced towers). Sole with small flattened cups with lateral spines and a few larger plates with undulated surface or smooth 4. Psolidiuin planum, new species 3. Dorsal side with no accessory' spicules ( ?). Ventral side with heavy knobbed plates and buttons 2. Psolidium eubullatum, new species 1. Psolidium dorsipes Ludwig Plate 29, Figs. 1-12 Psolidium dorsipes Ludwig, 1887, p. 9, pi. 2, fig. 9; 1894, p. 135 (passim). — Perrier, 1905, p. 48, pi. 2, figs. 5-15, text figures G-H. — Ekman, 1925, p. 112, text figure 26. Diagnosis. — Small form (sole 1 cm. long) ; ventral sole sharply set ofiF with 3 crowded bands of tube feet. Dorsal side covered by imbricating scales, about 10 between oral and anal scales; dorsal feet numerous, often 2-3 perforating a single scale; external layer of deposits well developed. Spicules in sole plates var^n'ng from smooth to knobbed, 2 types of plates, one with few holes, smooth or with few knobs, one with large holes and numerous pearllike knobs; also an external layer of cups with 4 knobs on the strongly convex side and a marginal brim of delicate teeth. Feet with end plate and oblong supporting plates, slightly curved, often with few knobs. Dorsal side with numerous baskets or cups of same size and tj'pe as in the sole; tube feet mostly with small end plate and walls packed with curved squarish plates, a few may be oblong. In some speci- mens numerous towers are present. Type. — Probably in Italy. Type locality. — Puntas Arenas, Strait of Magellan, 15-25 fms. Distribution. — Strait of Magellan and vicinity. Also Panama and Gulf of Calif. Depth. — From 6-60 fms. Specimens examined. — The following from the Allan Hancock Expeditions: 744-37. Near Point Piaxtla, Sinaloa, Gulf of Calif., 6-8 fms., April 1, 1937, 4 specimens (poor). 144 ALLAN HANCOCK PACIFIC EXPEDITIONS VOL. 8 863-38. Bahia Honda, Panama, off North Island, 30-50 fms., March 1, 1938, 1 specimen (fair). Remarks. — The Velero material differs from the material examined by Ludvvig and Perrier in the presence of the numerous towers with broad smooth base. The cups or baskets agree well with Ludwig's figure; possibly Perrier's drawing is somewhat inaccurate; the marginal teeth on the cups are too few and too coarse. It was a satisfaction to discover that the tube feet actually were packed with the curved squarish plates as was to be expected, not exclusively lying free in the skin as Perrier describes it; a few simple curved oblong plates may be found in the wall of the feet as in the other species. 2. Psolidium eubullatum, new species Plate 28, Figs. 4-7 Diagnosis. — Small form (type measures about 1 cm.). Sole with feet restricted to the margin and the anterior end of the midventral ambu- lacrum. Dorsal side with about 14 scales between oral and anal scales; dorsal feet few. Spicules in sole heavy buttons or plates with marginal and central knobs. Feet with end plate and perforated plates. Dorsal side apparently without any spicules except the scales; even the tube feet seem to lack spicules entirely. Type. — Holotype, AHF no. 38, 3 paratypes. Type locality.— S>\imon 213-34, La Plata Island, Ecuador, 7-10 fms., north of Anchorage, rocky, February 10, 1934, 3 specimens. Distribution. — Known from Ecuador. Depth. — From 7 to 55 fms. Specimens examined. — ^The type and 3 specimens from the following Velero stations : 212-34. La Plata Island, Ecuador, dredging 45-55 fms., sand shale, rock, mud, Februaiy 10, 1934, 1 specimen. 213-34. La Plata Island, Ecuador, 7-10 fms., February 10, 1934, type and 2 paratypes. Reinarks. — The specimens bear some resemblance to P. bullatum Ohshima, (1915, p. 282) from the Alaskan waters, 54 fms., and may possibly be found to be identical with that form. The unusually low depth at which it is taken is noteworthy, and information about the hydro- graphic conditions at La Plata Island is most desirable. NO. 3 DEICHMANN : HOLOTHURIOIDEA ; PART I, DENDROCHIROTA 145 3. Psolidium ekmani, new species Plate 30, Fig. 6 Diagnosis. — Small form (length of sole about 1 cm.). Oral and anal openings closed by indistinct valves ; stout radial teeth present inside the oral plates; about 5 scales between the oral and anal valves. Scales strongly sculptured with several pearllike projections, firmly attached; dorsal tube feet few. Sole with rows of marginal feet and a row of few feet scattered along the midventral ambulacrum. Spicules in sole delicate 4-holed buttons and plates with a larger number of holes ; a varying num- ber of knobs are present on the surface. Feet with end plate and support- ing rods. Dorsal side with no other spicules than the scales ( ?). Type. — Holotype, AHF no. 39, 1 paratype. Type locality.— Station 213-34, La Plata Island, Ecuador, 7-10 fms., dredging north of anchorage, Februaiy 10, 1934. Distribution. — From Ecuador to Panama. Depth. — From 7-10 fms. Specimens examined. — The type and one other specimen from the following Hancock stations : 213-34. La Plata Island, Ecuador, 7-10 fms., February 10, 1934, 1 specimen. 863-38. Bahia Honda, Panama, off North Island, rock, mud, sand, 30- 50 fms., March 1, 1938, 1 specimen. Re/narks. — The species was at first assumed to represent Psolus pata- goniciis Ekman, but comparison with the latter showed clearly that the spicules were entirely different (plate 30, fig. 8). Neither could it be referred to Psolus squamatus (Koren), var. segregatus Perrier because the projections on the scales were not loose but part of the scales. Also the presence of tube feet in the midventral ambulacrum separates it distinctly from both species mentioned above. Finally a few tube feet were dis- covered on the dorsal scales and the generic position thereby settled. The species is named in honor of Dr. Sven Ekman, the well-known zoogeog- rapher and student of holothurians, from Upsala, Sweden. 4. Psolidium planum, new species Plate 30, Figs. 1-5 Diagnosis. — Small form (sole up to 1.5 cm. long), body capable of becoming extremely flattened. Sole distinct; feet marginal and present as a scattered row of much smaller appendages in the midventral ambu- 146 ALLAN HANCOCK PACIFIC EXPEDITIONS VOL. 8 lacrum. Dorsal side with smooth imbricating scales, gradually decreasing in size around the oral and anal openings; tube feet few, small, easily overlooked. Entire dorsal surface covered by numerous large grains and other deposits, easily rubbed ofif. Spicules in sole an external layer of delicate smooth 4-holed flattened cups with marginal teeth. Beneath these a few larger plates may be found with several holes and smooth to undulating surface. Dorsal side closely packed with thimble-shaped grains with flattened basal plate (i.e., short, squat towers), besides numerous small baskets with delicate teeth and 4 apical knobs, sometimes united to a ring, thus approaching the hourglass shape. Tube feet with delicate end plate and circular or squarish curved supporting plates. (Tentacles not examined.) Type. — Holotype, AHF no. 40. Type locality.— Station 845-38, Sechura Bay, Peru, Lat. 5° 39' 30'' S.; Long. 81° 01' W., 9.5 fms., February 15, 1938. Distribution. — From Peru to Colombia. Depth. — From 9-60 fms. Specimens examined. — The following specimens from the Hancock Expeditions : 845-38. Sechura Bay, Peru, coarse sand, worm tubes, red algae, 9.5 fms., February 15, 1938, 3 specimens. 854-38. Gorgona Island, Colombia, north of island, mud, rocks, 40-60 fms., February 24, 1938, 1 specimen. Remarks. — The species has been referred to Psolidium because the cups in the dorsal integument are mostly simple and the feet on the sole are few. The dorsal spicules are easily rubbed off, but the spicules in the sole are so characteristic that it seems impossible to confuse it with any other species. Genus 3. PSOLUS Oken, 1815 Diagnosis. — Typical psolids with distinct sole with marginal tube feet, often also a band of feet along the midventral ambulacrum. Dorsal side covered by scales, few to many ; oral and anal apertures with or with- out an operculum of triangular scales ; sometimes narrow radial teeth present inside of and between these valves. No appendages on dorsum except the anal papillae and in some forms a few tube feet on the intro- vert. Tentacles 10 in number, the 2 ventral may be smaller; in some deepwater forms the tentacles are unbranched, finger shaped. Inner NO. 3 DEICHMANN: HOLOTHURIOIDEA ; PART I, DENDROCHIROTA 147 anatomy typical of the family; third loop of the intestine seems always to be attached in the right ventral interambulacrum. Spicules in sole plates or buttons, smooth or knobbed, in some forms reduced with age, in others transformed into reticulated masses. Feet usually with end plate and supporting rods. Dorsal side has besides the scales often grains, rarely a few cups are present. Introvert and tentacles with or without rods or plates; sometimes spicules reduced, in older in- dividuals. Type species. — Psolus phantapus (Strussenfeldt). Remarks. — The genus comprises about 30 difiFerent species and repre- sents apparently the most successful and widespread of the genera included in the family. A number of the species are exceptionally large (sole more than 10 cm. long) . The members of the genus occur in tropical as well as in Arctic seas. The Hancock Expeditions have secured only one species, but 2 others are discussed below to emphasize the diflferences between the species. One represents a common form ranging from the Strait of Magellan to the southern part of Bering Sea; the other, although hitherto known only from the vicinity of Cape Horn, may possibly be expected in the southern- most part of the Panamic region although it is not likely. Key to the Species of Psolus Known from the Panamic Region AND West Coast of South America 1. Dorsal scales large but few (2-3 between oral and anal valves) . Oral and anal valves large. Small form. Spicules in sole knobbed plates 3. Psolus diomedeae Ludwig 1. Dorsal scales more numerous 2 2. Spicules in sole slightly hollow buttons and plates with small holes and large marginal knobs. Distinct oral valves. . . . 2. Psolus patagonicus Ekman 2. Spicules in sole flat, mostly 4-holed buttons reduced with age. Dorsal side with few large round grains; oral valves indistinct. . . 1. Psolus squamatus (Koren), var. segregatus Perrier 1. Psolus squamatus (Koren), var. segregatus Perrier Plate 30, Fig. 7 Psolus squamatus (Koren), var. segregatus Perrier, 1905, p. 59. — Ekman, 1925, p. 136, text figure 33. 148 ALLAN HANCOCK PACIFIC EXPEDITIONS VOL. 8 Psoitis squamatus H. L. Clark, 1901, p. 165; 1901, p. 491.— Ohshima, 1915, p. 280. P solus pauper, Liidwig, 1894, p. 139. Diagnosis. — Large form (sole up to 13 cm. long) ; scales thin, smoothly overlapping, about 12 between oral and anal scales. Oral and anal apertures surrounded by a number of triangular scales but not de- veloped as regular valves, except in very young individuals. Sole thin, with marginal feet. Spicules in sole 4-holed delicate buttons (0.07-0.09 mm.) with shorter or longer marginal projections, sometimes with a few low warts ; often the spicules disappear with age. Feet with end plate and few perforated rods. Dorsal scales covered by a varying number of loose grains. Type. — Paris. Type locality. — Patagonia. Distribution. — From Cape Horn to the southern part of Bering Sea. Depth. — In the Patagonian waters ranging from 7-207 fms. ; in the northern waters taken between 155-603 fms. Specimens examined. — About 50 in the U.S.N.M. and Hopkins Ma- rine Station from various Albatross stations. Remarks. — The specimens examined agree with Perrier's form seg- regatus from Cape Horn except in minor points (equal development of the gonads and slightly different position of the paired retractors, prob- ably because of a different degree of contraction). The material has been compared with the typical form from Norway and shows the same differ- ences as those which Ekman has tabulated. Ludwig's P. pauper from the west coast of Mexico represents a small specimen of var. segregatus in which the spicules in the sole are unusually scarce. Ludwig's "antarcticus" from off Peru, which has always been regarded with suspicion, is most likely a small specimen of segregatus (or a specimen of Psolus patagonicus Ekman or of Psolidium ekmani). The young individuals of P. squamatus, var. segregatus may superficially re- semble either of these two forms. 2. Psolus patagonicus Ekman Plate 30, Fig. 8 Psolus patagonicus Ekman, 1925, p. 140, text figures 35-36. Diagnosis. — Small form (sole up to 2 cm. long) with distinct oral and anal valves and radial teeth inside the valves. Few scales between oral and anal valves; often smaller scales intercalated between the pri- NO. 3 deichmann: holothurioidea ; part i, dendrochirota 149 mary scales. External side of scales with pearllilce projections, rare or totally lacking in j^oung individuals which may have a few loose grains. Sole distinct with 1-2 marginal rows of feet. Spicules in sole slightly con- cave 4-holed buttons (0.12 mm.) with relatively small holes and a varying number of knobs on the surface, sometimes the knobs are united by crossbars. Feet with end plate and perforated plates (0.18 mm.). Tentacles with broad perforated plates. Type. — Hamburg. Type locality. — Patagonian Bank, Lat. 46° S. Distribution. — The type locality and various localities in the Strait of Magellan. Specimens examined. — Various individuals from Albatross Station 2777, and 2 received from the Museum in Buenos Aires. Remarks. — The species is mentioned because it resembles Psolidium ekmani. It was not secured by the Allan Hancock Expeditions and it seems not likely that it will be found in the Panamic region. 3. Psolus diomedeae Ludwig Plate 11, Figs. 9-10 Psolus diomedeae Ludwig, 1894, p. 136, pi. 14, figures 1-3. — Fisher, 1907, p. 717 (passim). Diagnosis. — Small form (sole less than 2 cm.) with enormous oral and anal valves; radial teeth present inside to the valves. Dorsal scales few and large, 2-3 between oral and anal valves; scales covered by few but large grains; sole with marginal feet. Spicules in sole strongly knobbed plates with 4 central holes and smaller marginal ones. (Feet and tentacles not examined.) Ty/.^.— U.S.N.M. Type locality. — Off Cocos Island, Costa Rica. Distribution. — From Gulf of California to Ecuador including Gala- pagos. Depth. — From 7-80 fms. Specimens examined. — The type in Washington and the following specimens from the Velero stations : 143-34. Wenman Island, Galapagos, 100-150 fms., Januaiy 11, 1934, 1 specimen. 213-34. La Plata Island, Ecuador, 7-10 fms., February 10, 1934. 38 specimens. 150 ALLAN HANCOCK PACIFIC EXPEDITIONS VOL. 8 429-35. Octavia Bay, Colombia, north end of channel, coarse sand and gravel, 35-40 fms., January 27, 1935, 1 specimen, young. 431-35. North of Octavia Bay, Colombia, south end of channel, 45 fms., January 27, 1935, 1 specimen. 529-36. Off San Francisquito Bay, Gulf of Calif., shale and gray mud, 165 fms., March 1, 1936, 1 specimen. 780-38. Chatham Bay, Cocos Island, Costa Rica, 40-47 fms., January 14, 1938, 3 specimens. 792-38. Off Daphne Minor Island, Galapagos, 70-80 fms., January 20, 1938, 1 specimen. 854-38. North of Gorgona Island, Colombia, 40-60 fms., February 24, 1938, 1 specimen, young. Remarks. — The species is very striking and cannot be mistaken for any other Pacific form, except the closely related P. macrolepis Fisher from Hawaii, 154 fms. depth. The latter has almost smooth plates in the sole and small basal scales intercalated between the oral valves. The depth, 7-10 fms., for the specimens from La Plata Island, is unusually low for this species and may indicate that peculiar hydrographic conditions prevail in that locality. NO. 3 DEICHMANN : HOLOTHURIOIDEA ; PART I, DENDROCHIROTA 151 BIBLIOGRAPHY Ayres, W. O. 1852. Description of a new species of Holothuria. Proc. Boston Soc. Nat. Hist., vol. 4, pp. 207-208. Clark, H. L. 1901. The Holothurians of the Pacific Coast of North America. Zool. Anz., vol. 24, pp. 162-171, 14 text figures. 1901a. The Holothurioidea ; Synopses of North-American Invertebrates 15. Amer. Nat., vol. 35, pp. 479-496, 27 text figures. 1910. The Echinoderms of Peru. Bull. Mus. Comp. Zool., vol. 52, No. 17, pp. 331-358, pis. 1-14. 1923. The Echinoderm Fauna of South Africa. Ann. South African Mus., vol. 13, pp. 221-435, pis. 8-23. 1938. Echinoderms from Australia. Mem. Mus. Comp. Zool, vol. 55, pp. 1-596, pis. 1-28. Deichmank, E. 1930. The Holothurians of the Western Part of the Atlantic Ocean. Bull. Mus. Comp. Zool., vol. 71, No. 3, pp. 43-226, pis. 1-24. 1936. A New Thyone from the West Coast of Mexico. Proc. New England Zool. Club, vol. 15, pp. 63-66, text figures. 1937. Holothurians from the Gulf of California. The Templeton Crocker Expedition, 9. Zoologica, Neiu York Zool. Soc, vol. 22, pp. 161-176, text figures 1-3. 1938. Holothurians from the Western Coast of Lower California and Central America, and from the Galapagos Islands; Eastern Pacific Expeditions of the New York Zoological Society, 16. Zoologica, New York Zool. Soc, vol. 23, pt. 4, pp. 361-387, text figures 1-15. 1938a. New Holothurians from the Western Coast of North America and some remarks on the genus Caudina. Proc. New England Zool. Club, vol. 16, pp. 103-115, text figures. 1939. A New Holothurian of the genus Thyone. Smithsonian Miscellaneous Collections, vol. 98, no. 12, pp. 1-7, text figures 1-3. DuBEN, M. W. V. & KOREN, J. 1844. Om Holothuriernes Hudskelet. Kgl. Vetensk. Akad. Handl., pp. 211-228, pis. 4-5. 1844a. Ofversig af Skandinaviens Echinodermer. Ibid., 1844 (1846), pp. 229- 338, pis. 6-11. Edwards, C. L. 1910. Four species of Pacific Ocean Holothurians allied to Cucumaria fron- dosa (Gunnerus). Zool. Jahrb., Abt. Syst., vol. 29, pp. 597-612, pi. 19. Ekman, S. 1923. Ueber Psolus squamatus und verwandte Arten. Arkiv f. Zoologi, vol. 15, pp. 1-56, 37 text figures. 1925. Further Zoological Results of the Swedish Antarctic Expedition, 1901-3, vol. 1, No. 6., pp. 1-199, 37 text figures. Fisher, W. K. 1907. The Holothurians of the Hawaiian Islands. Proc. U.S. Nat. Mus., vol. 32, pp. 637-744, pis. 66-82. 152 ALLAN HANCOCK PACIFIC EXPEDITIONS VOL.8 Forbes, E. 1841. A History of British Starfishes and other Animals of the Class Echino- dermata, London, pp. I-XX, 1-267, with text figures. GOLDFUSS, G. A. 1820. Handbuch der Zoologie, Pt. 1-2, pp. I-XLVI, 1-696, pis. 1-4. Heding, S. G. 1936. Echinoderms, 6 & 7 Thule Expeditions. Medd. Gronland, vol. 108, No. 1, pp. 1-34, text figures 1-6. Herouard, E. 1901. Note preliminaire sur les Holothuries rapportees par I'Expedition Antarctique Beige. Arch. Zool. Exp., notes 3, 9, pp. XXXIX-XLVIII. Jager, G. F. 1833. De Holothuriis. (Dissertation Inauguration). Turin, pp. 1-40, pis. 1-3. KOREN, J. Beskrivelser over Thyone fusus og Cuviera squamata. Nyt. Mag. f. Naturvid., vol. 4, 1844-45, pp. 203-225, pis. 1-2. Lampert, K. 1885. Die Seewalzen, Holothurioidea, eine systematische Monographic, JViesbaden, pp. 1-310, pi. 1. Lesson, R. P. 1830. Centurie Zoologique, Paris, pp. 1-244, pis. 1-80. LUDWIG, H. 1875. Beitrage zur Kenntniss der Holothurien mit Nachtrag. Arbeiten aus d. Zool.-Zoot. Institut in Wiirzburg, vol. 5, pp. 77-120, pis. 6-7. 1883. Verzeichniss der Holothurien des Kieler Museums. Berlin Oherh. Ge$., vol. 22, pp. 155-176. 1887. Die von G. Chierchia auf der Fahrt der Kgl. Corvette "Vettor Pisani" gesammelten Holothurien. Zool. Jahrb., vol. 2, pp. 1-36, pis. 1-2. 1887a. Drei Mittheilungen iiber alte und neue Holothurienarten. Sitzungsber. Akad. Berlin, pp. 1217-1244 (reprint pp. 1-28), pi. 15. 1894. The Holothurioidea. Reports on an Exploration oflF the West Coasts of Mexico, Central and South America, etc. Mem. Mus. Camp. Zool,, vol. 17, No. 3, pp. 1-183, pis. 1-19. 1898. Holothurien. Hamburger Magelhaenische Samraelreise, pp. 1-98, pis. 1-3. 1904. Brutpflege bei Echinodermen. Zool. Jahrb., suppl. vol. 7, pp. 683-699. MiiLLER, J. 1854. Ueber den Bau der Echinodermen, Abhandl. Berlin Akad. Wiss., pi. 9, fig. 9. Ohshima, H. 1912. On the System of Phyllophorinae with Descriptions of the Species found in Japan. Annot. Zool. Japan, Tokio, vol. 8, pp. 53-96, pi. 1, text figures 1-7. 1915. Report on the Holothurians collected by the U.S. Fisheries Steamer Albatross in the Northeastern Pacific during the Summer of 1906. Proc. U.S. Nat. Mus., vol. 48, pp. 213-291, pis. 8-11. NO. 3 DEICHMANN : HOLOTHURIOIDEA ; PART I, DENDROCHIROTA 153 Oken, L. 1815. Lehrbuch der Naturgeschichte, vol. 3, Zoologie, Jena, pp. 351-352. Pallas, P. S. 1766. Zoophytorum sistens generum adumbrationes, etc., Hagae comitum, pp. 1-451. Perrier, R. 1904. Holothuries du Cap Horn. Bull. Mus. d'Hist. Nat., vol. 10, pp. 11-17. 1905. Holothuries antarctiques du Museum d'Histoire Naturelle de Paris. Ann. Set. Nat., vol. 9, pt. 1, pp. 146, pis. 1-5, text figures. Sars, M. 1857. Bidrag til Kundskaben om Middlehavets Littoral Fauna. Nyt. Mag. Naiurvidenskab, pp. 57-155, pis. 1-2. (Contribution to our knowledge of the littoral fauna of the Mediter- ranean Sea.) Selenka, E. 1867. Beitrage zur Anatomie und Systematik der Holothurien. Zeit. JViss. Zool., vol. 17, pp. 291-372, pis. 17-20. 1868. Nachtrag. Ibid., vol. 18, pp. 109-119, pi. 8. Semper, C. 1868. Reisen in Archipel der Philippinen. Wiss. Res., Pt. 1, Holothurien, pp. 1-288, pis. 1-40. Sluiter, C. p. 1880. Ueber einige neue Holothurien von der West-Kuste Javas. Naturkund. Tijdschr. Nederl. Ind., pp. 1-28, pis. 1-7. 1901. Die Holothurien der Siboga Expeditie. Uitkomst H. M. Siboga . . . uit- geven van Max Weber; Monograph 44, Leiden, pp. 1-142, pis. 1-11. Theel, H. 1886. Report on the Holothurioidea. Report on the Scientific Results of the Voyage of H.M.S. Challenger during the years 1873-1878. Pt. 39, Zool- ogy, vol. 14, pp. 1-290, pis. 1-16. 1886a. Report on the Holothurioidea. Report on the Results of the Dredgings by the U.S. Coast Survey Blake. Bull. Mus. Camp. Zool., vol. 13, pp. 1-21, pi. 1. Troschel, F. H. 1846. Neue Holothurien Gattungen. Arch. f. Naturgesch., vol. 12, pt. 1, pp. 60-66. Verrill, a. E. 1866. On the Polyps and Echinoderras of New England. Proc. Boston Soc. Nat. Hist., vol. 10, pp. 333-357. 1867. Notes on the Echinoderms of Panama and West Coast of America with descriptions of new genera and species. Notes on the Radiata of Yale College, etc.. No. 2. Trans. Conn. Acad. Arts & Sciences, vol. 1, pp. 251-322. 1867. Supplementary note on the Echinoderms of the West Coast of America. Ibid., p. 376. \ 154 ALLAN HANCOCK PACIFIC EXPEDITIONS VOL. 8 EXPLANATIONS OF PLATES Magnification: Scale divisions indicate %oo i"™- PLATE 10 Cucumaria crax, new species p. 83 1. Supporting rod from tube foot. 2-5. Crackerlike button from integument. Cucumaria californica Semper p. 79 6-7. Knobbed plate from integument. 8. Supporting rod from tube foot. NO. 3 DEICHMANN: HOLOTHURIOIDEA; parti, DENDROCHIROTA PL. 10 I I I I I 1 1 I I I 1 1 1 1 1 I I I 1 1 1 156 ALLAN HANCOCK PACIFIC EXPEDITIONS VOL. 8 PLATE 11 Cucumaria duhtosa Semper P- 81 1. Knobbed plate with handle from integument, 2. Supporting rod from tube foot. Cucumaria chilensis Ludwig P- 80 3. Knobbed plate (medium sized) from integument. 4. Button from integument. 5. Supporting rod from tube foot. NO. 3 DEICHMANN : HOLOTHURIOIDEA ; PART I, DENDROCHIROTA PL. 1 1 I I I I I M I I I I I I I I I I I I I I 158 ALLAN HANCOCK PACIFIC EXPEDITIONS VOL. 8 PLATE 12 Pentamera beehei Deichmann p. 86 1-6. Supporting tables from feet. 7-9. Tables from integument. Pentamera zacae Deichmann p. 85 10-11. Supporting tables from tube foot. 12-17. Acorn-shaped bodies from integument. NO. 3 DEICHMANN: HOLOTHURIOIDEA; PARTI, DENDROCHIROTA PL. 12 15 16 li J_L 160 ALLAN HANCOCK PACIFIC EXPEDITIONS VOL. 8 PLATE 13 Apentamera lepra, new species p. 92 1-2. Supporting tables from tube foot. 3-4. Rosettes (or flat baskets) from outer layer of spicules. 5-6. Knobbed plates from inner layer of spicules. 7-8. Tables from introvert. 9-10. Rod and plate from tentacles. NeopentaTnera anexigua, new species p. 90 11. Supporting rods from tube foot. 12-14. Knobbed buttons from integument. Pentamera cliiloensis (Ludwig) p. 88 15-17. Tables from integument, lateral view and from above (spire omitted in the latter cases). 18. Supporting table from tube foot. Pentamera chierchia (Ludwig) p. 86 19-20. Tables from integument. 21. Supporting rod from tube foot. NO. 3 DEICHMANN: HOLOTHURIOIDEA ; PART I, DENDROCHIROTA PL. 13 I I I I I I I I I I I I I I I I 162 ALLAN HANCOCK PACIFIC EXPEDITIONS VOL. 8 PLATE 14 Leptopentacta grtsea H. L. Clark p. 93 1-2. Baskets from external layer of integument. 3-4-. Buttons from external layer of integument. 5. Supporting plate from tube foot. Leptopentacta panamica, new species p. 96 6-7. Baskets from external layer of integument. 8-10. Knobbed buttons from external layer of integument. 11. Supporting table from tube foot. 12. Small-holed plate with spinelike projection, from external layer of integument or wall of tube foot. Leptopentacta nova, new species p. 95 13-15. Irregularly knobbed button from external layer of integument. 16. Large swollen button from external layer of integu- ment. 17-19. Biscuit-shaped plates from external layer of integu- ment. 20-22. Biscuit-shaped plates with marginal tooth from ex- ternal layer of integument. NO. 3 DEICHMANN: HOLOTHURIOIDEA ; part I, DENDROCHIROTA PL. 14 164 ALLAN HANCOCK PACIFIC EXPEDITIONS VOL.8 PLATE 15 Leptopentacta ntna, new species p. 97 1-2. Hollow plates or buttons from external layer of integument. 3. Larger plate from external layer of integument. 4-9. Irregular knobbed buttons from inner layer of integu- ment. 10-12. Supporting plates from tube foot. XO. 3 DEICHMANN: HOLOTHURIOIDEA ; PART I, DENDROCHIROTA PL. 15 I I I I I I I I I I 166 ALLAN HANCOCK PACIFIC EXPEDITIONS VOL.8 PLATE 16 Pentacta peruana (Semper) P- 97 1-3. Baskets from external layer of integument. 4-6. Knobbed buttons from inner layer of integument. 7. Supporting plate from tube foot. 8. Knobbed plate from inner layer of integument near base of tube foot. NO. 3 deichmann: holothurioidea ; part i, dendrochirota pl. 16 168 ALLAN HANCOCK PACIFIC EXPEDITIONS VOL. 8 PLATE 17 Thyonacta mexicana, new species p. 101 1-5. Baskets from external layer of integument. 6-9. Smaller knobbed buttons from inner layer of integu- ment. 10. Large knobbed button from inner layer of integu- ment. 11-13. Supporting plates, knobbed and smooth, from tube feet. NO. 3 DEICHMANN : HOLOTHURIOIDEA ; PART I, DEVDROCHIROTA PL. 1 7 I I I I I I I I I I I I I 170 ALLAN HANCOCK PACIFIC EXPEDITIONS VOL. 8 PLATE 18 Thyone neofusus, new species p. 104 1. End plate from tube foot. 2-3. Tables from integument. 4-5. Supporting tables with no trace of spire. 6. Disk of table from introvert. Thyone parafusus, new species p. 106 7-9. Oblong tables with tapering spire and "handle." 10-11. Supporting tables with 3 pillars in spire. 12. Disk of table from introvert. Thyone bidentata, new species _ p. 105 13-14. Tables from integument. 15. Incipient table. All from type. 16. Supporting table from a small individual less than 1 cm. long. NO. 3 DEICHMANN: HOLOTHURIOIDEA ; PART I, DENDROCHIROTA PL. 18 172 ALLAN HANCOCK PACIFIC EXPEDITIONS VOL.8 PLATE 19 Thyone strangeri, new species p. 107 1-5. Tables from integument. 6-8. Tables from introvert. 9-10. Supporting tables with conical spire from tube foot. 11. Rosette from tentacle. NO. 3 deichmann: holothurioidea; parti, dendrochirota pl. 19 I I I I 1 I I I I I I I I I I 174 ALLAN HANCOCK PACIFIC EXPEDITIONS VOL.8 PLATE 20 Neothyone gibber (Selenka) p. 109 1-4. Knobbed to smooth buttons. 5-6. Knobbed button from external layer, lateral view showing the external cluster of spines and the inner "handle." 7. Supporting table from tube foot. 8. Table from introvert. 9. Supporting rod from tentacle. All from Selenka's type in M.C.Z. NO. 3 deichmann: holothurioidea; parti, dendrochirota pl. 20 I I I I I I I I I I I I I I I 176 ALLAN HANCOCK PACIFIC EXPEDITIONS VOL.8 PLATE 21 Neothyone panainensis (Ludvvig) p. 112 1-2. Supporting plates from ventral feet. 3-4. Knobbed plates from inner layer of integument. 5-6. Baskets derived from buttons from external layer of integument. Neothyone gibbosa, new species p. 113 7-8. Knobbed buttons (outer handle often with 3 knobs) from inner layer of integument. 9. Knobbed button from external layer of integument, with a few spines (rare). 10-11. Supporting tables from tube foot. NO. 3 deichmann: holothurioidea; part i, dendrochirota pl. 21 178 ALLAN HANCOCK PACIFIC EXPEDITIONS VOL.8 PLATE 22 Neothyone gibbosa, new species p. 113 1-3. Large deformed supporting tables from dorsal feet of large individual from San Felipe, Gulf of Cali- fornia. 4. Basketlike buttons from outer layer of integument (rare). 5-6. ICnobbed buttons from inner layer of integument. 7. Small smooth supporting plate from ventral tube foot. 8. Table from introvert (disk obviously somewhat re- duced through reduction along the margin). Pachythyone pseudolugubris, new species p. 116 9-10. Supporting tables from tube foot, dorsal and ventral, respectively, from large individuals from San Felipo, Gulf of California. NO. 3 deichmann: holothurioidea; part i, dendrochirota pl. 22 I I I I I I I I I I I I I I I I I I I I I 180 ALLAN HANCOCK PACIFIC EXPEDITIONS VOL.8 PLATE 23 Pachythyone fseudolugubris, new species p. 116 1-2. Supporting tables from ventral tube feet of specimens few cm. long. 3-5. Knobbed buttons from inner layer of integument. 6. Knobbed plate from outer layer seen from the inter- nal side (the reticulated external layer is not drawn). Pachythyone lugubris (Deichmann) p. 116 7-8. Elongate knobbed buttons from inner layer of integu- ment. 9. Supporting table from ventral tube foot. Pachythyone rubra (H. L. Clark) p. 115 10. Supporting table from ventral tube foot. 11-12. Knobbed buttons from inner layer of integument. NO. 3 deichmann: holothurioidea; part I, DENDROCHIROTA PL. 23 I I 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 182 ALLAN HANCOCK PACIFIC EXPEDITIONS VOL. 8 PLATE 24 Euthyonidium ovulum (Selenka) p. 12+ 1-6. Plates with or without trace of spire. 7. Supporting rod from tube foot. Euthyonidium veleronis, new species _ p. 126 8-10. Plates with few spires, indicating traces of a spire. 11. Plate from introvert. Phyllophorus zacae Deichmann p. 134 12-15. Disks of tables. 16-17. Tables, lateral view. 18. Disk of supporting table from tube foot. 19-20. Supporting tables, lateral view. 21. Rosette from tentacle. NO. 3 DEICHMANN: HOLOTHURIOIDEA; part I, DENDROCHIROTA PL. 24 ' I I 1 1 1 1 I I 1 1 1 1 1 1 1 1 I 1 1 1 184 ALLAN HANCOCK PACIFIC EXPEDITIONS VOL.8 PLATE 25 Phyllophorus aculeatus Ludwig p. 133 1-3. Tables seen from above. 4. Large supporting table from tube foot, lateral view. 5. Disk of supporting table, seen from above. 6. Disk of table from introvert. 7. Rosette from tentacle. 8. Delicate rods from tentacle. NO. 3 DEICHMANN : HOLOTHURIOIDEA ; PART I, DENDROCHIROTA PL. 25 186 ALLAN HANCOCK PACIFIC EXPEDITIONS VOL. 8 PLATE 26 Thyonepsolus nutriens H. L. Clark p. 138 1. Curved supporting plate from dorsal tube foot. 2-3. Hourglass-shaped bodies from dorsal side. 4. End plate from dorsal tube foot. 5. Perforated plate from ventral sole. Thyonepsolus 'veleronis, new species p. 140 6-8. Knobbed plates from ventral sole. NO. 3 DEICHMANN : HOLOTHURIOIDEA ; PART I, DENDROCHIROTA PL. 26 I I I I I I I I M M I I I 188 ALLAN HANCOCK PACIFIC EXPEDITIONS VOL.8 PLATE 27 Thyonepsolus hancocki, new species P- 140 1-2. Knobbed buttons from ventral sole. 3. Curved supporting plate from dorsal tube foot. 4-5. Hourglass-shaped bodies from dorsal side. 6-7. Perforated plates from stem of tentacle. Thyonepsolus veleronis, new species p. 140 8. Curved supporting plate from dorsal tube foot. 9. Hourglass-shaped body from dorsal side. NO. 3 DEICHMANN : HOLOTHURIOIDEA ; PART I, DEXDROCHIROTA PL. 27 ^U 190 ALLAN HANCOCK PACIFIC EXPEDITIONS VOL. 8 PLATE 28 Thyonepsolus beebet Deichmann p. 139 1. Perforated plate from ventral sole. 2. Curved supporting plate from dorsal side. 3. Hourglass-shaped body from dorsal side. Psolidium eubullatum, new species p. 144 4-7. Knobbed plates from ventral sole. NO. 3 DEICHINIANN : HOLOTHURIOIDEA ; PART I, DENDROCHIROTA PL. 28 192 ALLAN HANCOCK PACIFIC EXPEDITIONS VOL. 8 PLATE 29 Psolidium dorsipes Ludwig ?• 1+3 1-2. Knobbed and smooth plates from ventral sole. 3-4. Strongly knobbed plates from sole. 5. Supporting rod from ventral tube foot. 6. Towerlike body from dorsal side. 7. Curved supporting plate from dorsal tube foot. 8-10. Cups or baskets from external layer of sole and dorsal side. 11. Narrow, curved supporting rod from dorsal tube foot (rare). 12. End plate from dorsal tube foot. NO. 3 DEICHMANN : HOLOTHURIOIDEA ; PART I, DENDROCHIROTA PL. 29 Li 194 ALLAN HANCOCK PACIFIC EXPEDITIONS VOL.8 PLATE 30 Psolidium planum, new species P- 1^5 1-3. Shallow buttons or baskets from external layer in sole. 4. Smooth plate in deeper layer of sole. 5. Curved plate from tube foot in dorsal. Psolidium ekmanij new species - p. 1+5 6. Knobbed button from sole. Psolus squamatus (Koren), var. segregatus Perrier p. 147 7. Button from sole. Psolus patagonicus Ekman p. 148 8. Slightly hollow button with marginal knobs from sole. Psolus diomedeae Ludwig p. 149 9-10. Knobbed to almost smooth plates from sole. NO. 3 DEICHMANN : HOLOTHURIOIDEA ; PART I, DEXDROCHIROTA PL. 30 I I M I I I I I I I I M I REPORTS ON THE COLLECTIONS OBTAINED BY ALLAN HANCOCK PACIFIC EXPEDITIONS OF VELERO III OFF THE COAST OF MEXICO, CENTRAL AMERICA, SOUTH AMERICA, AND GALAPAGOS ISLANDS IN 1932, IN 1933, IN 1934, IN 1935, IN 1936, IN 1937, IN 1938, IN 1939, in 1940, and in 1941. NEW EASTERN PACIFIC SEA STARS (Plates 31-34) By FRED C. ZIESENHENNE The University of Southern California Publications Allan Hancock Pacific Expeditions Volume 8, Number 4 Issued October 14, 1942 The University of Southern California Press Los Angeles, California CONTENTS Introductory Remarks Family ASTROPECTINIDAE Genus Leptychaster Smith Subgenus Parastropecten Ludwig Leptychaster (Parastropecten) stellatus, new species . . p. 197 Family BENTHOPECTINIDAE Genus Luidiaster Studer Luidiaster calif ornicus, new species p. 201 Family LINCKIIDAE Genus Phatar'ta Gray Phataria mionactis, new species P- 206 Genus Tamaria Gray Tamaria obstipa, new species P- 208 Family ASTERIIDAE Genus Coronaster Perrier Coronaster marchenus, new species P- 210 NEW EASTERN PACIFIC SEA STARS (Plates 31-34) Fred C. Ziesenhenne Research Assistant Allan Hancock Foundation During the last ten years the Velero III, research cruiser of the Allan Hancock Foundation, The Universit}^ of Southern California, on various scientific cruises to the eastern tropical Pacific and southern California waters has dredged an extensive collection of sea stars, including the fol- lowing new species. In keeping with the policy of making expedition results immediately available, it has been thought advisable to publish on the new species rather than to await the final report on the Asteroidea. The writer acknowledges his indebtedness to Dr. H. L. Clark of the Museum of Comparative Zoology, Harvard College; to Mr. A. H. Clark of the U. S. National Museum ; and to Dr. W. K. Fisher of the Hopkins Marine Station for valuable and helpful suggestions in the preparation of the manuscript. Thanks are due Mr. Anker Petersen, staff artist of the Allan Hancock Foundation, for the drawings and recording of color notes, and Mr. G. P. Ashcraft of the Allan Hancock Foundation for the accompanying photographs. Last, but not least, the author expresses grateful appreciation to Cap- tain Allan Hancock for the privilege of participating in most of the Velero III expeditions and for the opportunity of a trip east to study and compare many of the specimens with type material of the U. S. National Museum and the Museum of Comparative Zoology. Astropectinidae Genus LEPTYCHASTER Smith Subgenus Parastropecten Ludwig Leptychaster (Parastropecten) stellatus, new species Plate 31, Figs. 1-3 Description.— Rzys 5, R=15 mm., r=6 mm., R=2.5 r. Width of ray at second marginal plate 6 mm. Disk moderate, rays about as long as width of disk, gradually tapering to a bluntly pointed tip ; general form depressed. Abactinal paxillar areas not crowded, paxillae arranged in [197] 198 ALLAN HANCOCK PACIFIC EXPEDITIONS VOL. 8 regular, transverse, oblique rows at sides of ray and median interradial area; no definite arrangement of paxillae in the center of disk. Paxillae largest at base of ray and interradial areas, decreasing conspicuously in size toward the center of disk and tip of ray. Column of paxilla slightly higher than width of base, constricted at the summit. The largest bear 10 short spinelets constricted at the base and greatly enlarged into a finely serrated sphere at the tip. Each paxilla bears 1 or 2 central spinelets and up to 9 in the peripheral series ; smaller paxillae carry only 4 or 5 periph- eral spinelets, not reduced in size. Abactinal plates are small, compact along the midradial line and cen- ter of the disk where papulae are lacking. The plates of the papular areas in general are circular with 4 to 6 lobes, irregular in length, thickness, and distribution. Plates of the papular areas are arranged in regular transverse oblique rows, parallel with the interradial line. There are 6, often 5, and occasionally 4 papulae around each plate, emerging from between the lobes by which the plates usually touch. Plates along the median area of the ray are even less regular, often without lobes ; they are slightly small- er, and the papulae are absent from a median strip about three plates wide. Toward the center of the disk the plates rapidly decrease in size, they become more crowded, and lobes if present are inconspicuous and of irregular occurrence. Superomarginal plates 18 from median interradial line to tip of ray, forming an arched bevel to border the abactinal area. They are rectangu- lar, with a convex surface, about three times wider than long, largest interradially and gradually decreasing in size distally. Marginal plates of both series are separated transversely by deep, narrow, fasciolar grooves, and a deep longitudinal groove separates the supero- from the inferomarginal plates. Superomarginal plates covered with numerous, close-set, finely serrated capitate spinelets. The marginal spinelets are slightly smaller and more delicate. The heavier, coarse, median spinelets are arranged in 3 transverse rows on the interradial marginals, then 2 rows on median plates, and a single row on the most distal plates. They are about the same size as the actinal, paxillar spinelets. Terminal plate large, conspicuous, its length equal to the width of four adjoining superomarginal plates; abactinal surface broadly convex; proximal margin with a broad concave notch ; distal margin blunt, with a deep furrow groove. Distal half naked, proximal half covered with capitate spinelets, which diminish gradually in size distally, where they are only one third the size of those on the proximal margin. NO. 4 ziesenhenne: new eastern pacific sea stars 199 Inferomarginal plates 20, of the usual form, about as wide as length of three plates interradially, whence the width rapidly diminishes toward end of ray. The outer end of the first two plates is narrower than the inner. The outer end of the plates, forming the rounded ventrolateral border of the ray, is closely covered with rather truncated capitate spine- lets similar to those of the superomarginals (but projecting a little farther outward) ; but on the actinal surface these become slenderer, clavate, with the thorny ends sometimes obliquely pressed, or bent, toward mar- gin of ray. There are no enlarged tubercles on any marginal plate. Actinal interradial areas small, comprising 2 complete chevrons of plates. The inner chevron, without an odd interradial, extends to fourth inferomarginal; the second, with a conspicuous unpaired interradial, reaches to the second plate, while outside the odd plate are two others indicating a third and fourth chevron to come. The plates have a low tabulum, carrying a few capitate spinelets, like those on outer end of inferomarginals, and also usually a few slender clavate ones. Adambulacral plates 26, with an angular furrow margin, a convex surface, and somewhat sunken transverse sutures. The first few plates are wider than long, but they continue to narrow distally until on outer third of ray they are longer than wide. Furrow spines proximally 4, but over most of ray 3, subspatulate, blunt, the median member with edge to furrow. There are proximally 9 or 10, distally about 6, clavate, thorny subambulacral spinelets a little smaller than the furrow members, ar- ranged in about 3 longiseries proximally and 2 distally. The distal mem- ber of the longiseries often stands on the furrow margin and can reason- ably be counted as a fourth or fifth furrow spinelet. Mouth plates relatively large, the suture length about twice width of combined plates. Furrow margin more than half suture length. Furrow spines about 6, increasing in size toward apical spine, which is heavy, clavate, and blunt. There are 10 or 12 suboral spinelets along margin of median suture; 5 or 6 on margin adjacent to first adambulacral, and 4 or 5 scattered in between. Madreporite oval, convex, diameter 1.25 mm., raised above disk plates, located in the median interradial area along the superomarginals. Striations coarse, irregular, centrifugal, arched domelike. IVIadreporite surrounded by 6 large paxillae, which often conceal it. Color. — Dried, actinal surface is cream bulif, abactinal surface and marginals yellow cream buff. Holotype. — AHF no. 44; 7 paratypes. 200 ALLAN HANCOCK PACIFIC EXPEDITIONS VOL. 8 Type locality. — Holotype and 2 paratypes from Station 701-37, 32 fms., sand and shell, Angeles Bay, Gulf of California, Mexico, March 20, 1937. Four paratypes from Station 650-37, 47 fms., coarse sand, off San Francisco Island, Gulf of California, Mexico, March 9, 1937. One para- type from Station 1249-41, 34-44 fms., fine white sand, one mile south of San Benito Islands, Lower California, Mexico, February 26, 1941. Remarks. — The youngest specimen measures R=5.2 mm., r=3.2 mm., R=1.6 r, width at base of ray (second superomarginal plate) 2.7 mm. It has 7 very large, rectangular superomarginal plates separated from one another by deep fasciolar grooves, and 14 adambulacral plates. The terminal plate is conspicuous, large and convex, raised above the abactinal surface. Anal aperture is barely visible. Paxillae bear a central and 6 or 7 peripheral spinelets. There are 3 or 4 ambulacral furrow spines. Each mouth plate bears 3 large oral spines. Actinal interradial series consists of 7 plates. The madreporite is small, partly concealed by crowded paxillae, and located in the median interradial area. Relative Dimensions of Leptychaster (Parastropecten) stellatus Station R (mm.) r (mm.) R.r fVidth at raybase (mm.) No. of supero- marginals No. of adambu- lacrals 701-37 15 6 2.5:1 6 18 26 701-37 7.6 3.8 2:1 3.4 14 18 701-37 10 4.2 2.3:1 4.2 16 23 1249-41 7.8 3.8 2:1 3.4 11 18 650-37 10 5.3 1.8:1 4.6 14 20 650-37 6 3.7 1.7:1 2.8 8 14 650-37 5.2 3.2 1.6:1 2.7 7 14 650-37 5.4 3.1 1.7:1 2.7 7 14 This species is closely related to Leptychaster (Parastropecten) in- ermis (Ludwig) of the tropical Pacific but differs from it in having 6 papulae instead of 4 around each plate; proximally 4, rarely 5, and dis- tally 3 furrow spines instead of 6 or 7 ; a more stellate disk, longer arms, NO. 4 ziesenhenne: new eastern pacific sea stars 201 and very- large, conspicuous terminal plate instead of a pentagonal disk and small inconspicuous terminal plates. It differs from the northern Pacific Leptychaster (Parastropecten) anomalus Fisher by the following characters : L. (P.) stellatus Paxillar spinelets coarse, clavate. Central paxillar spinelets 1 or 2. Peripheral paxillar spinelets up- ward of 9. L. (P.) anomalus Paxillar spinelets slender, terete. Central paxillar spinelets 3 or 4. Peripheral paxillar spinelets up- ward of 10. Ambulacral spines proximally 4, Ambulacral spines proximally 5 or rarely 5, distally 3. Furrow margin of adambulacral plate angular. Actinal spinelets clavate, less nu- merous. Terminal plate large and conspicu- ous. Disk stellate. Adambulacral plates shorter. First adambulacral plate com- pressed. Adults have 18 superomarginals, 26 adambulacrals. 6, distally 4 or 5. Furrow margin of adambulacral plate convex. Actinal spinelets slender, tapering, numerous. Terminal plate small and incon- spicuous. Disk pentagonal. Adambulacral plates longer. First adambulacral plate not com- pressed. Adults have 16 superomarginals, 29 adambulacrals. The name stellatus has reference to the long, narrow rays in contrast to the usual short-rayed, pentagonal forms. Benthopectinidae Genus LUIDIASTER Studer Luidiaster californicus, new species Plate 31, Figs. 4-5; Plate 32, Figs. 1-7 Description. — Rays 5, R=87 mm., r=16 mm., R=5.43 r. Breadth of ray at base 19 mm. Abactinal surface of the disk and basal portions of the rays slightly swollen. Abactinal integument composed of large circu- lar plates interspaced with numerous small, irregular, round and elon- gated plates. A section of integument cleared in xylene revealed the plates as irregularly arranged and close together, but not in actual contact. The smaller plates serve as connectives between the larger ones, and the papu- \0 202 ALLAN HANCOCK PACIFIC EXPEDITIONS VOL. 8 lae pass through the interspaces. As seen from the coelomic surface, on the basal part of arm and adjacent disk integument, are 3 longitudinal series of large plates, a median and 2 lateral rows, where the large plates are compacted with fewer small connectives and no intervening papulae. The plates are low and form 3 simple kinds of intergrading paxillae. The tabulum is only slightly elevated, and the smallest plates bear from 1 to 8 short, bluntly pointed, granulelike spinules. The intermediate plates bear one long, stout, tapering, movable spine and a surrounding ring of 1 to 5 sharp spinules of varying length and size, and on the base of the tabulum a circle of short granulelike spinules. The largest of the intermediate plates bear 1 to 3 equally long central spines and 1 to 6 slightly shorter secondary spines. The largest paxillar plates confined to the disk and basal ray usually bear a long, sharp, movable central spine and 4 to 9 equal or subequal spines surrounding it. There is considerable variation as to the length and density of these spines. These paxillae are free of secondary spinelets and bear comparatively few granulelike spinules on the edge of the tabulum. Dorsal spines are largest on the center of the disk, where they are about 3 mm. long and fairly stout. The paxillar armature de- creases rapidly in size distally and beyond the papular areas only the small single-spinuled and granulelike spinule forms are present. The differences between the large, small, and intermediate paxillae are more distinct on the disk and papular areas of the rays than on nonpapular areas. The in- termediate paxillar plates are in the process of forming large paxillar plates bearing the long primary spines. Marginal plates of two alternate series. There is no encroaching of the superomarginals upon the abactinal area except far along the rays. Each plate is strongly convex, almost tabulate, bearing 1 or 2, often 3, movable tapering spines, the uppermost usually the largest, equal in length to the combined length of three superomarginal plates. These are sur- rounded by 2 to 7 secondary spines of varying length, less than one third the length of the largest spine. On the remainder of the plate, except for the naked border, are numerous, well-spaced, short, blunt, granulate spinules. The plates of both series have their raised portion separated by shallow, naked channels. The spines of the first and second superomar- ginal plates are shorter than the succeeding ones. Inferomarginal plates are slightly wider than superomarginals. The central portion of each plate is elevated to form a transverse spine-bearing ridge. Each ridge bears 2 or 3, often 4, rigid but movable, tapering, pointed subequal, outstanding spines, the central or uppermost the largest. NO. 4 ziesenhenne: new eastern pacific sea stars 203 They are stouter and somewhat longer than the corresponding supero- marginal spines. There are fewer secondary spines and spinules compared with the superomarginals. The terminal plate is small, wider than long, densely covered with spinules. Adambulacral plates more than twice as wide as long, widely sepa- rated by deep, broad, naked grooves. The center of the plate is raised in a prominent, transverse ridge bearing 3 or 4 subequal, stout, tapering spines, the longest more than the combined length of two adambulacral plates. The outermost spine slightly the longest. In addition, there may be from 3 to 9 sharply tapering spinelets on the outer edge of ridge. Furrow mar- gin ridge prominent, bearing 2 to 4 subequal, heavy, blunt, slightly curved, capitate furrow spines, the outer two shortest, middle one or pair equal to the length of one adambulacral plate. Tube feet in 2 rows ; suck- ing disks well developed, ampullae double. Mouth plates oval shaped, more than twice as long as wide; actino- stomial margin widest, broadly rounded; distal margin narrow, convex; actinal surface highly convex. Marginal spines, 5 or 6, broad and flat- tened, tapering and bluntly tipped. Innermost spine longest, about two thirds the length of oral plate, next shorter, and the remaining diminish- ing rapidly in size to the short, delicate outer spine. On the actinal sur- face are 3 to 5 large, stout, tapering, blunt spines, half the length of oral plate and 2 to 4 smaller secondary spines. Distally on each plate is a longitudinal row of 3 to 8 short, sharp spinules. Actinal intermediate plates 4 to 8, confined to the disk, oval shaped, wider than long, each bear- ing 3 to 5 transverse rows of 3 to 4 short, sharp, granulelike spinules. Papulae very numerous, absent in a narrow interradial line of the disk and the distal two thirds of the ray. They are present on the disk and basal portion of ray, where there is some semblance of 4 longitudinal rows, each with an irregular transverse series of 3 to 6 papulae. Longitudinal rows are separated by 3 longitudinal rows of loosely compacted, large paxillar plates ; the two central rows consist of 2 or 3 transverse papulae, extending to the third or fourth superomarginal. Outer rows consist of 3 to 5 transverse papulae, extending to sixth, seventh, or eighth supero- marginal ; and in larger specimens there is a continuation of a single row of papulae, close to the superomarginals extending to the thirteenth su- peromarginal. In a specimen of R=90 mm. each papular area contained about 260 papulae. The youngest specimen of R=32 mm. contained 62 papulae in each papular area. 204 ALLAN HANCOCK PACIFIC EXPEDITIONS VOL. 8 Pectinate pedicellariae very inconspicuous, flat, confined to the actinal surface. One or 2 pedicellariae in each actinal interradial area, and up- ward of 13 have been found on a ray between the adambulacral plates. The margins of 2 adjacent plates each bear a comb of 5 to 7, straight, broad, short, bluntly tipped, interlocking spinules. Pectinate pedicellariae could not be found on all of the specimens. Madreporite body convex, striae radiate out irregularly. It is located in the interradius about its own diameter (1 or 2 plates) from the supero- marginal plates; surrounded and protected by 4 or 5 large paxillae. On the coelomic surface of the dorsal integument are 2 long, narrow, strong muscle bands, extending from the basal portion to the tip of the rays. Proximally they are separated, but on the distal third of ray they join, continuing as a single band to the tip of ray. The proximal tendon is from 8 to 10 mm. long. In the larger specimens the main portion of the tendon is attached fanwise to the proximal side of the crest of the promi- nent ninth or tenth ambulacral ossicle. The attachment is not noticeably fanwise in the smaller specimens. Small lateral tendons branch off and are attached to the third, fourth, fifth, and sometimes the sixth superomargi- nal plate. Color. — In alcohol, the ground color is dull cream buff, lightly over- cast with gray, papular areas slightly darker gray; spines almost white with tinges of cream buff. Holotype. — AHF no. 45 ; 7 paratypes. Type locality. — Holotype and 6 paratypes from Station 1306-41, 228-267 fms., loose rock, submarine bank 6 miles east of Long Point, Santa Catalina Island, California, May 3, 1941. An additional paratype from Station 1425-41, 280 fms., loose rock, 11.5 miles S.E. of Church Rock, Santa Catalina Island, California, September 28, 1941. Remarks. — There is some variation in the length and number of spines on the paxillae; some bear secondary spines, some have just spi- nules surrounding the large central spines, and others, mainly on the larg- est specimens, have a central spine surrounded by equally large spines. There are other variations already mentioned. The youngest specimen of R==32 mm., r=5 mm., had no papulae in the center of the disk, the nar- row interradial area, longitudinal center of the proximal part of ray, and distal two thirds of ray. In each area there were about 62 papulae, which extend out in 2 double rows to the fifth and a single row to the ninth su- peromarginal. The armature of the plates and of the paxillae was es- sentially the same as in the larger specimens. No pectinate pedicellariae were observed. NO. 4 ziesenhenne: new eastern pacific sea stars 205 From Ltiidiaster dawsoni (Verrill) of Alaskan waters this species differs as follows: Luidiaster dawsoni Abactinal paxillae with short spines surrounding the central spine. Paxillar spinules long, sharp, dis- tinct. Large, prominent, circular pecti- nate pedicellariae on actinal and abactinal surfaces, composed of 2 or 3 combs of 12 or less long, heavy, stronglj^ recurved spin- ules, almost L-shaped. Adambulacral furrow spines 5-7. Adambulacral actinal spines 2-4. Actinostomial oral spines 6-8. Suboral spines 7-10. Muscle tendon attached to 7th or 8th ambulacral ossicle and 3rd superomarginal. Madreporite in young nearly touching superomarginal. Papulae absent from center of disk. Luidiaster calif ornicus Abactinal paxillae with long spines, surrounding the central spine and often equal in length. Paxillar spinules short, blunt, granulelike. Small, inconspicuous, flat pectinate pedicellariae confined to actinal surface, composed of 2 combs of 7 or less short, broad, blunt, straight spinules. Adambulacral furrow spines 3 or 4. Adambulacral actinal spines 2 or 3, rarely 4. Actinostomial oral spines 5 or 6. Suboral spines 3-5. Muscle tendon attached fanwise to 9th or 10th ambulacral ossicle and 2 or 3 lateral tendons to 3rd, 4th, 5th, or 6th superomar- ginal. Madreporite more than its diame- ter from superomarginals. Papulae present on center of disk, except young. This species is distinct from Luidiaster horridus (Fisher) of the Ha- waiian Islands as follows: Luidiaster horridus No pectinate pedicellariae. Luidiaster calif ornicus Pectinate pedicellariae present ac- tinally. Oral plates with 3 enlarged spin- Oral plates with 3-5 actinal promi- ules. ntnt spines. 206 ALLAN HANCOCK PACIFIC EXPEDITIONS VOL. 8 Inferomarginal spines 5-8. Inferomarginal spines 2 or 3, rare- ly 4. Paxillae with accessory spines two Paxillae with accessory spines often thirds the length of central equal the length of central spine, spine. Actinostomial marginal spines 7. Actinostomial marginal spines 5 or 6. Actinal oral spines 10 or 11. Actinal oral spines 3-5. Papulae absent from center of disk. Papulae present on center of disk. The name calif orntcus has reference to the known distribution of this species. Linckiidae Genus PHATARIA Gray Phataria mionactis, new species Plate 33, Figs. 3-4 Description. — Rays 5, R^50 mm., r==10 mm., R=5 r. Rays short, heavy, and bluntly pointed, more or less cylindrical and tapering slightly toward the tips. Height of ray at base 9.5 mm., at ray tip 6 mm. Width of ray at base 11 mm., midray 10 mm., ray tip 8 mm. Skeleton composed of numerous, irregular, swollen, compacted, granulated plates. The disk is covered with large and small, irregular plates; the larger plates are ar- ranged in an irregular circle within the .ray bases. Within the circle and surrounding the anal opening are about 27 irregularly shaped plates of various sizes. The plates are compactly covered with coarse, mosaiclike granulations, which are round or rectangular. The granules surrounding the anal aperture are heavier and longer. The broad abactinal surface of the ray is covered with large and com- pact plates of irregular shapes and sizes, between which are often wedged smaller, irregular plates. Transversely there are about 5 plates across the arm, irregularly placed and overlapping without a definite serial arrange- ment. On the sides of the rays are 2 regular series of papular areas of about 20 pores each. The upper series, immediately above the supero- marginal plates, averages 17 areas and extends to within 8 mm. of the ray tip. The lower or intermarginal series averages 22 areas and extends to the tip of the ray. The papular areas, which are separated one from another by a single transversely oriented plate, are reinforced by a reticu- lation of tiny ossicles which serves to separate the papulae and support the granules. NO. 4 ziesenhenne: new eastern pacific sea stars 207 Marginals regularly arranged, lateral; the plates of the two series of the same size, roughly rectangular, and united in dorsoventral pairs by the secondary ossicle which separates the papular areas. The plates of each series are strongly imbricated, free edge adoral, and they also overlap the interpapular secondary plates; superomarginals about 18, inferomar- ginals 20. Actinal plates abruptly much smaller than inferomarginals, in 3 per- fectly regular series, with the beginning of a fourth at interradius. They also form regular transverse series of 3, two of these corresponding to an inferomarginal. Actinal granules become gradually coarser toward fur- row. Adambulacral plates compressed, somewhat crescent shaped, concave distally, the actinal aspect about as broad as the furrow length of two suc- cessive plates. Armature consists of a spatulate subtruncate furrow spine with a shorter, much slenderer aboral companion; immediately behind these (without intervening granules) stands a compressed, generally abovate spine, about as long as the major furrow spine, and a secondary aboral spinelet smaller than the corresponding one of the furrow series. Back of these the plates are granulated as the adjacent actinals. Along the margin of the extremely narrow furrow there are thus 2 series of short, compressed spines (each with an inconspicuous companion). Madreporite subcircular, slightly concave, 2 mm. in diameter, with numerous small pores but no obvious carinae. It is in contact with 2 inter- radial superomarginals. Color. — Dried, light vinaceous buff. Color in life, abactinal surface maroon with 2 purple longitudinal bands covering the papular areas, the upper band terminating short of the ray tip and the lower band extend- ing to the ray tip. Actinal surface creamish buff. Type.—ARY no. 41. Type /ocfl//7y.— Station 212-34, 45-50 fms., La Plata Island, Ecua- dor, Februai-y 10, 1934. Remarks. — The rays of this specimen are unusually short. This con- dition might be caused by a pathological disease or mechanical injury. Many coral-dwelling fishes, especially the parrot fishes, are known to bite off sea star rays and even stout sea urchin spines. Upon examination ter- minal constrictions were noted suggesting regenerating ray tips. Com- pared with Pharia and Phntoria, specimens in which ray tips were regen- erating, the type differed by having short, blunt, and less tapering ray tips, while the other specimens had longer, decidedly tapering ray tips term!- 208 ALLAN HANCOCK PACIFIC EXPEDITIONS VOL. 8 nating in blunt points, and the regenerating ray was distinct from the older portion. The short, robust, nontapering blunt arms, 2 regular series of margi- nal plates, 2 regular series of lateral papular areas, and the very broad abactinal area distinguish this species from other members of the family Linckiidae in the eastern tropical Pacific. The type locality was again visited by the Velero III in 1935 and 1938 in the hope of collecting additional specimens of this unique species, but none were obtained. The name mionactis (less-ray) refers to the rays that are shorter than usual. Genus TAMARIA Gray Tamaria obstipa, new species Plate 33, Figs. 1-2; Plate 34, Fig. 1. Description. — Rays 5, R=36 mm., r=7 mm., R=5 r. Rays slender and tapering; width at base 8 mm., midray 6 mm., ray tip 3.5 mm. Disk slightly convex, plates swollen, to one side of the central plate is the anal aperture. The plates of ray are disposed in the following series: at base of ray, 3 abactinal, 4 marginal, 6 actinal in addition to a series of secondary intermarginals ; at middle of ray, 2 actinal series less ; near tip of ray, 1 abactinal (carinal), 4 marginal, actinal. All of the plates are covered with closely compacted, rounded or polygonal granules ; those on the con- vex surface of the plates are larger than those in the depressed areas be- tween the plates. There is no definite arrangement of the granules, except in the depressions between the plates where single, transverse rows often mark the margins of the plates, leaving between them a noticeable trans- verse furrow, especially distinct in the abactinal and marginal series. The papular areas are arranged in 6 rows; 4 abactinal series extend two thirds of the ray; they are not continuous; often there are 2 or 3 plates in succession without papular areas. Intermarginal series regular, reaching within a few plates of ray tips. Papulae in each area vary from 6 to 24, distally some areas had as few as 3. There are no papular areas on the actinal surface. The adambulacral plates about three times as broad as long, about 3 plates opposing 2 of the adjoining series. Each plate bears a large sub- ambulacral and 2 smaller furrow spines in addition to numerous enlarged granules. The adambulacral armature consists of 2 distinct rows of spines, set close together; those on the furrow are small, flat, blunt, chisellike, NO. 4 ziesenhenne: new eastern pacific sea stars 209 about as wide as long; the width is variable, often a broad spine opposing a narrow spine. They are convex on the outer side and concave on the furrow side, often with a narrow, distinct groove. The subambulacral row is composed of large, robust, spatulate, blunt-tipped spines, longer than wide, about four times as long and twice as wide as the furrow spines. Between the subambulacral spines are slightly enlarged granules, arranged in 1 or 2 series, transversely to the furrow. The mouth plates bear a prominent, enlarged, triagonal, apical oral spine, 2 oral marginal spines, and a prominent, spatulate suboral spine. Granulations on the proximal half of mouth plates small; distal of the suboral spine they be- come enlarged and spatulate. Alveolate pedicellariae on the abactinal surfaces; although lacking on the actinal surface of the holotype, they are abundant on the paratype. The distribution of pedicellariae, however, is of no specific importance. Abactinally the pedicellariae are well distributed ; actinally they are con- fined to a single series of 7 to 14 along the subambulacral spines; in sev- eral cases the pedicellariae have replaced the subambulacral spine on the adambulacral plate. The shape of the jaws varies from slightly bent to bifid ; they are thin, flaring widely at the tips and constricted at the base — some flare out widely and are notched to form a letter Y, while others flare asymmetrically to form a letter L. The majority resemble small socks. The sockets in which the pedicellariae lie are straight; the concavity and broad ridge of the socket face the ambulacra. The madreporite is 2.3 mm. in diameter and is located interradially about its own diameter from the center of the disk. The surface is covered with fine, close convolutions and striations that radiate from the center. The anal aperture in the center of the disk is closed by 6 long, narrow spinelets, longer than wide and a number of elongated granules. Color. — Dried from alcohol, light bufif with a faint lavender hue. Types. — Holotype AHF no. 42; one paratype. Type locality. — Station 780-38, 40-47 fms., Chatham Bay, Cocos Is- land, Costa Rica, January 14, 1938. One paratype from Station 183-34, 50-70 fms., James Bay, James Island, Galapagos, January 24, 1934. Remarks. — The paratype measures R=54 mm., r^lO mm., R=5 r. It has fewer papular areas, which are not continuous but alternate with the plates. The alveolate pedicellariae of the actinal surface are more abundant, 7 to 14; abactinal surface, 12 to 15. The anal aperture is closed by 8 small, triangular granules of different sizes. The groove on the fur- row spines is deeper and conspicuous. 210 ALLAN HANCOCK PACIFIC EXPEDITIONS VOL.8 This species is closely related to T. floridae (Perrier), the pedicel- lariae of which have small racquet-shaped jaws with a slender, long pedi- cel and a broad distal expansion with smooth, convex margin. T. sclero- derma (Fisher) is more distantly related. It has exceedingly tiny gran- ules, difficult to detect until the specimen is dried. The subambulacral spines are spaced from the furrow series, and the interval is thickly cov- ered with minute granules. The proximal furrow spinelets of T. sclero- derma have a rudimentaiy groove or concavity on the furrow face. The name obstipa has reference to the pedicellariae, which are bent out of a straight line. Asteriidae Genus CORONASTER Perrier Coronaster marchenus, new species Plate 33, Figs. 5-6; Plate 34, Figs. 2-6 Description. — Rays 11 to 17, deciduous; R^80 mm., R=8 r. Skeleton weak, reticulate, composed of numerous 3- to 5-lobed pri- mary plates connected by 1 to 4 slender, imbricated ossicles. Reticulum of disk irregular with much smaller meshes than that of the ray. These are veiy small in a zone at periphery of disk, where the plates are irregular and form a more solid framework. Between this peripheral frame and the first transverse arch of abactinal ray plates is a line of weakness where autotomy occurs. Primary plates of disk with a single acicular spine about 1.5 mm. long. Skeleton of ray is composed of 5 radial rows of slender, 3- to 5-lobed plates connected radially and transversely by narrow, elongated ossicles, forming 4 rows of subrectangular papular areas. The carinal row consists of 9 to 12 spine-bearing plates that extend to middle of ray, beyond which degeneration takes place, leaving only the marginals. On the distal half of ray gradual degeneration of longitudinally united secondaries has oc- curred. The larger specimens have proximally a dorsolateral series con- sisting of 5 to 8 spine-bearing plates confined to the basal third of ray. The superomarginal and inferomarginal series consists of 20 to 25 spinif- erous plates extending to ray tips. Each plate bears a large, acicular spine about 3 mm. long. The adambulacral plates are long, narrow, and set at a 45° angle to the furrow; the distal half of one plate overlaps the proximal half of the next plate on the furrow side. Each plate bears an oblique series of 2 NO. 4 ziesenhenne: new eastern pacific sea stars 211 blunt, heavy, tapering spines with an enlarged bulbous base, inner spine about 1.3 mm. long, outer spine 1.7 mm. long. Alternate adambulacral plates carry on the furrow face a straight pedicellaria. Tube feet are large, in 2 rows. Mouth plates rectangular, longer than wide ; each bears a large apical oral spine and 2, sometimes 3, and often even a fourth oral spine. Inner of furrow spines shortest, 1.3 mm. long; other spines larger, about 1.8 mm. long. These spines are flattened and widely flared out at the base, then taper distally to a cylindrical blunt tip. Under high power all fur- row spines are longitudinally ribbed and form a serrate edge on the spine tip. Papular areas of the disk are small and irregular, bearing a few pap- ulae and often free rudimentary ossicles. There are from 2 to 15 papulae in the large, rectangular-ray papular areas. Straight pedicellariae lanceolate, slender, 0.4 to 1 mm. long, scattered rather sparsely over plates, papular areas, and along the furrow face of adambulacrals. The largest have 3 short, curved teeth at distal end, while the smaller terminate in a short hook only. There are no hand-shaped unguiculate pedicellariae such as are present in C. volsellatus, C. briareus, and C. halicepus. Crossed pedicellariae of the spine wreaths vary from 0.27 to 0.45 mm. long. Each jaw is armed with 2 large terminal teeth between which are 6 small, sharp, triangular teeth about one half the length of the termi- nals. These teeth are curved downward and form an acute angle with the shank. The shank of the jaw is armed with a single series of 6 (vary- ing from 5 to 7) long, sharp, downward-curved hyaline teeth. The ter- minal teeth of the jaw give the pedicellariae the appearance of a minia- ture saber-toothed tiger skull. The pedicellariae of the furrow are 0.4 mm. long; distal four fifths of jaw is serrated and terminates in one or more long, curved claws. They are found on alternate adambulacral plates. Madreporites, 1 to 5, a large and 4 small accessory madreporites. The largest is 4 mm. long and 2 mm. wide; it is composed of 2 small madreporites fused together. The 4 smaller madreporites are 1.5 mm. in diameter. All five are located about their diameter from the edge of the disk. The striations radiate irregularly from the center, except the large madreporite, where they run parallel transversely to the long axis. Color. — In life, abactinal surface creamish white with carmine stria- tions running radially and transversely, more noticeable distally. The radial and transverse rows of skeletal plates light gray, papulae and papu- 212 ALLAN HANCOCK PACIFIC EXPEDITIONS VOL. 8 lar areas darker gray, wreaths of pedicellariae on spines commonly buff, often varying from cream to a rich orange. Regenerating arms somewhat lighter, salmon to orange in color. Actinal surface light gray, tube feet pale yellow. When dried, ground color on abactinal surface of the disk deep walnut brown; color extends on basal half of arm and gradually fades distally to olive buff at tips; network of plates and spines olive-buff with a tinge of brown. Actinal side similar in color but lighter in tone. In alcohol, very pale purplish gray. Holotype. — AHF no. 43; 33 paratypes. Type locality. — Holotype and 10 paratypes from Station 310-35, 15 fms., tangles, Marchena Island, Galapagos, December 3, 1934. Twenty- three additional paratypes as follows: 2 from Station 307-35, 20 fms., tangles, Marchena Island, Galapagos, December 3, 1934; 3 from Station 308-35, 3-5 fms., sand, north bay, Marchena Island, Galapagos, Decem- ber 3, 1934; 14 from Station 773-38, 31-50 fms., coralline bottom, off Nuez Island, Cocos Island, Costa Rica, January 13, 1938 ; 3 from Station 779-38, 30-50 fms., rock, coral, and coralline, off Nuez Island, Cocos Island, Costa Rica, January 14, 1938; and one from Station 795-38, 35- 40 fms., rock and sand, Sulivan Bay, James Island, Galapagos, January 21, 1938. Remarks. — That this species is fissiparous is well borne out by a study of the 34 specimens examined, in which 11 was the minimum and 17 the maximum number of rays, 13 the average per individual. Specimens with a ray length less than 50 mm. averaged 12.7 rays, while those exceeding 50 mm. ray length averaged 13.6 rays. Exclusive of the holotype, 49.3 per cent of the rays were young or regenerating rays. Madreporites ranged from 1 to 5 per individual, 3 being the average; 24 per cent of the madre- porites were on young or regenerating portions of disk. In fissiparous re- production a portion of the disk is cast away with the rays. The small madreporites and regenerating rays grow from this section of regenerating disk, which in some specimens is very distinct. There is no definite order or arrangement in the manner the new rays are added to the disk. In gen- eral, 5 or more rays of a first set grow from the regenerating disk ; then at a later period a few scattered rays of a second set appear between the adult rays. In some specimens a third set of rays appears between the re- generating first set just opposite the old adult rays. The average ray length to the disk radius for 20 of the largest specimens is R=9.5 r. These are the first Coronasters to be recorded from the eastern tropi- cal Pacific Ocean and increase the number of Pacific species to 4: Coron- NO. 4 ZIESENHENNE: NEW EASTERN PACIFIC SEA STARS 213 aster volsellatus (Sladen) and Coronostcr halicepus Fisher, Philippine Islands, and Coronaster cclipes Fisher, Hawaiian Islands. jMarchenus, having 2 adanibulacral spines, cannot be confused with volsellatus. It differs from halicepus as well as briareus of the West Indies in lacking broad, unguiculate, hand-shaped, straight pedicellariae. In C. eclipes (described from a single ray) these unguiculate pedicellariae are also lacking; and the lanceolate type, so characteristic of marchenus, is found only on the furrow face of the adambulacrals. But the furrow pedicellariae of marchenus are similar to those of volsellatus and quite un- like the smaller more triangular ones of eclipes (see Fisher, Sea Stars Tropical Central Pacific, Bishop Museum Bulletin No. 27, 1925, p. 78, fig. 9 d, e, f). The crossed pedicellariae are essentially the same as those of volsellatus, with a similar wide range in size. Characteristic of mar- chenus are the fissiparous habit and the presence of upward of 5 madre- porites, features which have not been reported for the other species. The name marchenus has reference to Marchena Island, on whose rough lava reefs this species was taken in abundance. 216 ALLAN HANCOCK PACIFIC EXPEDITIONS VOL. 8 PLATE 31 Leptychaster (Parastropecten) stellatus, new species Fig. 1. Abactinal view of paxillae and mar- ginal plates X 10. Fig. 2. Abactinal view, scale in mm. Fig. 3. Actinal view, scale in mm. Luidiaster californicus, new species Fig. 4. Abactinal view. Fig. 5. Actinal view. N-O. 4 ZIESEXHEXXE : NEW EASTERN' PACIIIC SEA ST.^ \RS FL. 31 I ' L' • I I I I I I M 11 1. I I M , I , , , , iTTTT^T^t. 218 Ai.i.w" HWcocK PACIFIC lixi'Fnrnoxs voi.. H PLATE 32 /.uulidslrr < alijor/ii( lis, new species Fk;. 1. Abactinal view of dissection showing the muscle attachments of the dorsal integument to the 9th and 10th amhulacral ossicles and the side wall. Fk;. 2. Side view of the adambulacral armature. Fig. 3. Side view of the most ad\anced and largest type of abactinal paxilla. Fig. 4. Actinal view of the dorsal integument, upper part cut from the center of the disk and lower part from the proximal portion of the arm, showing large and small skeletal plates and papulae distribution. Fig. 5. Pectinate pedicellaria from the actinal inter- radia area. Fig. 6. Side-actinal \iew of upper and lower inarginal plates. Fig. 7. Actinal \iew of mouth jilates showing arma- ture. NO. 4 ZIESEXHEXXi: : XFW EASTERX I'ACiriC SEA STARS I'l.. ^2 4 mm. 220 \\A.\S HANCOCK PACIFIC EXPEDITIONS VOL. 8 PLATE 33 Tarn aria ohstipa, new species Fig. 1. Ahactinal vie\v. Fig. 2. Actinal view. Phataria mionactis, new species Fig. 3. Abactinal view. Fig. 4. Actinal view. Coronastcr marclienus, new species Fig. 5. Abactinal view. Fig. 6. Actinal view. NO. ziesexhexxe: xew easterx pacific sea stars PI. 33 ^^P^^^^^^l KEi ^^^^^^^ \ ^^^^^^^^^^^^1 ■1^ ' ~ -^^H 797 ALLAN- HANCOCK I'ACIFIC FXI'f- DITIOXS VOL. 8 PLATE 34 Tainaiia obstipn. new species Fig. 1. .Retinal view showing adambulacral armature ami three pediceliariae. Coranaslcr itiardunus, new species Fig. 2. Larj^e, straight abactinai pedicellaria. Fig. 3. Small, straight abactinai pedicellaria. Fig. +. Ambulacra! furrow pedicellaria. Fig. 5. End view of a crossed pedicellaria showint; ar- rangement of teeth. Fig. 6. Side view of a crossed pedicellaria. xo. 4 ZIKSEXHFXXH : XRW KASTERX PACITIC SEA STARS PI.. 34 '/lo m m HUBERT LYMAN CLARK: TEACHER AND FRIEND January 9, 1870 -July 31, 1947 Probably the two forms of activity which Dr. Hubert Lyman Clark enjoyed above all others were teaching and dredging for marine animals. It is perhaps appropriate, therefore, that this brief note of appreciation should be offered by one of the very few students Dr. Clark was destined to have during his long tenure at Harvard University and published through the generosity of Captain Allan Hancock, who made possible Dr. Clark's many happy days of dredging aboard the Velero III. No attempt is made to incorporate in this tribute an evaluation of his important contri- 11 butions to the study of echinoderms, indicated by the bibliography which follows; that appraisal should be reserved for other workers in his chosen field. My association with Dr. Clark began in 1930 when he agreed to supervise my graduate studies on Crustacea. At the time, my knowledge of Crustacea was extremely fragmentary, and he readily admitted his ignorance of some of the more involved aspects of crustacean classification. Thanks to his insistence that the best way to learn the relationships of any group was by direct examination of as many of the representative forms as possible, both of us eventually gained an adequate working knowledge of this diverse assemblage of animals. As this form of training entailed the drudgery of checking identifications, relabeling specimens, and re- arranging the crustacean collections in the far reaches of the catacomb-like basement of the Museum of Comparative Zoology, the assignment was not consistently welcomed or understood by a young taxonomist who associated systematic work with somewhat more significant tasks in a less obscure environment. Not until several years later did the value of this fundamental curatorial training become apparent to the recipient. I am sure that Dr. Clark appreciated his student's mild discomfort, and I will always be grateful that he had the courage of conviction to see to it that this apprenticeship was fully served. In subsequent years, as a member of the staff at the Museum of Comparative Zoology, I became better acquainted with Dr. Clark and came to recognize his loyal friendship as one of the most important and valued associations of my life. Although he was unusually reticent about offering unsought criticism of any kind, he was always eager to be of assistance whenever his advice was solicited. His almost emotional grati- tude for all favors returned in kind was a unique characteristic familiar to all who came in close contact with him. Except for an attack of yellow fever suffered during a collecting trip to Jamaica in 1896, from which he was the only one of six victims to survive, Dr. Clark enjoyed remarkably good health until his last illness. Always one to minimize his infrequent minor indispositions, he sometimes found it difficult to appreciate the reaction of others to similar disorders. The bout with yellow fever had a profound effect upon his later life, however, for it left him with impaired hearing which showed progressive deterioraion with the passage of time. This affliction seemed to affect in no way his optimistic outlook toward life, but it did virtually force his retirement from classroom teaching, which he so enjoyed, and prevented ui intimate contact with his fellow men; this, to a man of Dr. Clark's friendly disposition, must have been a heavy cross to bear, but I cannot recall that he ever referred to it with the least trace of bitterness. His unusual robust health was reflected in his general mental outlook. Whether the activity involved was his scientific work, caring for his valuable stamp collection, playing tennis, or climbing his beloved New Hampshire mountains, all of which were indulged in until the last year of his life, Dr. Clark believed in giving the best that was in him. The only times that I have seen him violently incensed about anything were on those infrequent occasions when he discovered a typographical error he had overlooked in one of his publications or lost a point at tennis which he felt should have been his with a little additional skill or effort, and at these times his anger was always directed at himself. In his scientific work, he was prone to set goals and deadlines for himself and he did his best to adhere to these even when it meant driving himself far into the night. This is a characteristic which may seem questionable to others of us acquainted with the unpredictability of taxonomic research, but it was a fundamental part of Dr. Clark's nature and one which apparently sei-ved him well. No insight into Hubert Lyman Clark's character would be complete without reference to his religious activities. An ardent churchman, he thoroughly believed that the Sabbath was a day to be set aside for worship and human companionship. All who accompanied him on field trips will recall how determined he was that Sunday, as far as he was concerned, was not a day for collecting, no matter how propitious the weather or the tide. This religious nature was at the root of his entire philosophy of life. As he once expressed himself in print, he put his faith in a "confident belief in oneself, in a loving God and in our fellow men as children of one Father." Only on some such foundation as this did he feel that one could build a satisfying personal philosophy which, in his words, "must give full scope to the mind, ... set no arbitrary limits to human knowledge, . . . encourage and stimulate the quest for truth and have no fear thereof wherever found, . . . allow full play for the emotions, . . . [and] . . . provide a fundamental motive, a driving power for an achieving life." Fenner a. Chace, Jr. U. S. National Museum July 16, 1948 IV Bibliography of Dr. H. L. Clark's Echintoderm Papers Compiled by Marjorie Pattee, Research Assistant, M.C.Z. 1896. Notes on the life history of Synapta vivipara Oerstedt. Jour. Jamaica Inst. '' July, vol. 2, pp. 278-282. The viviparous Synapta of the West Indies. Zool. Anz., September 14, vol. 19, no. 512, pp. 398-400. 1897. The viviparous Synapta of the West Indies. Johns Hopkins Univ. Circulars, November, vol. 17, pp. 2-3. 1898. Notes on the echinoderms of Bermuda. Ann. N. Y. Acad. Sci., September, vol. 11, pp. 407-413. Synapta vivipara: a contribution to the morphology of echinoderms. Mem. Boston Soc. Nat. Hist., vol. 5, no. 3, pp. 53-88, pis. 11-15. Synapta 'vi'vipara: a contribution to the morphology of echinoderms. Mem. Biol. Lab. Johns Hopkins Univ., vol. 4, no. 2, pp. 53-88. The echinoids and asteroids of Jamaica. Johns Hopkins Univ. Circulars, November, no. 137, pp. 4-6. 1899. Further notes on the echinoderms of Bermuda. Ann. N. Y. Acad. Sci., vol. 12, pp. 117-138, pi. 4. The Synaptas of the New England coast. U.S. Fish- Comm. Bull., December 13, pp. 21-31, pis. 10, 11. 1901. Bermudan echinoderms. A report on observations and collections made in 1899. Proc. Boston Soc. Nat. Hist., vol. 29, no. 16, pp. 339-345. The echinoderms of Porto Rico. U.S. Fish Coram. Bull., vol. 2, pt. 2, pp. 231-263, pis. 14-17. The holothurians of the Pacific Coast of North America. Zool. Anz., March 25, vol. 24, no. 639, pp. 162-171. Synopses of North American invertebrates: The holothurioidea. Am. Nat., June, vol. 35, pp. 479-496. The breeding habits of holothurians. Mich. Acad. Sci. Third Rep., pp. 83-85. Echinoderms from Puget Sound. Proc. Boston Soc. Nat. Hist., vol. 29, no. IS, pp. 323-337, 4 pis. 1902. Notes on some North Pacific holothurians. Zool. Anz., Julv, vol. 25, pp. 562-564. Echinodermata papers from the Hopkins Stanford Galapagos Expedition, 1898-1899. Proc. Wash. Acad. Sci., September 30, vol. 4, pp. 521-531. 1904. Echinoderms of Woods Hole region. U.S. Fish Comm. Bull, for 1902, pp. 545-576, pis. 1-14. 1905. Fauna of Nevp England: List of the Echinodermata. Occ. Papers, Boston Soc. Nat. Hist., February, vol. 7, pp. 1-13. 1906. List of echinoderms available for exchange in the M.C.Z. September, pp. 1-8. 1907. With A. Agassiz. Hawaiian and other Pacific Echini. The Cidaridae. Mem. M.C.Z., Februar3', vol. 34, no. 1, 50 pp., 44 pis. With A. Agassiz. Preliminary report on the Echini collected, in 1902, among the Hawaiian Islands, by the U.S. Fish Commission Steamer "Albatross." Bull. M.C.Z., March, vol. 50, no. 8, pp. 231-259. The starfishes of the genus Heliaster. Bull. M.C.Z., vol. 51, no. 2, pp. 25-76, 8 pis. Recent literature on echinoderms. Science, July, n. s. vol. 26, pp. 12-17. With A. Agassiz. Preliminary report on the Echini collected in 1906, from May to December, among the Aleutian Islands, in Bering Sea, and along the coasts of Kamtchatka, Sakhalin, Korea, and Japan, by U.S. Fish Com- mission Steamer "Albatross." Bull. M.C.Z., October, vol. 51, no. 5, pp. 109-139. As to holothuria. Science, October, n. s. vol. 26, pp. 549-550. The Cidaridae. Bull. M.C.Z., December, vol. 51, no. 7, pp. 165-230, 11 pis. The apodous holothurians. Washington, January 1908, Smithsonian Cont. to Knowl., vol. 35, 231 pp., 13 pis. 1908. A brittle star new to the Woods Hole region. Science, January, n. s. vol. 27, p. 147. Some Japanese and East Indian echinoderms. Bull. M.C.Z., April, vol. 51, no. 11, pp. 279-311. Renewed interest in recent crinoids. Am. Nat, May, vol. 42, pp. 350-355. 7 The type of Cidaris. Ann. Mag. Nat. Hist., June, ser. 8, vol. 1, pp. 532-533. With A. Agassiz. Hawaiian and other Pacific Echini: The Salenidae, Arbaciadae, Aspidodiadematidae, and Diadematidae. Mem. M.C.Z., September, vol. 34, no. 2, pp. 43-132, 17 pis. Les Cidaridae. Bull. Soc. Sci. Nat. Haute-Marne, 5^ Ann., no. 22, pp. 165-228. 1909. Abstract of unpublished paper: Brood-protection and sexual dimorphism among echinoderms. Science, n. s. vol. 29, p. 711. With F. A. Bather. The type of Cidaris. Ann. Mag. Nat. Hist., January, ser. 8, vol. 3, p. 88. Notes on some Australian and Indo-Pacific echinoderms. Bull. M.C.Z., March, vol. 52, no. 7, pp. 109-135. , Scientific results of the trawling expedition of H.M.C.S. "Thetis" off the coast of New South Wales, in February and March 1898. Echinoderraata. Australian Museum Mem. 4, pt. 11, pp. 519-564, 11 pis. I With A. Agassiz. Hawaiian and other Pacific Echini. The Echinothuridae. Mem. M.C.Z., November, vol. 34, no. 3, pp. 135-206, pis. 60-89. 1910. A new ophiuran of the West Indies. Proc. U.S. Nat. Mus., August 19, vol. 37, pp. 665-666. The echinoderms of Peru. Bull. M.C.Z., October 10, vol. 52, no. 17, pp. 321-358, 14 pis. The development of an apodous holothurian. (Chiridota rotifera). Jour. Exp. Zool., November, vol. 9, pp. 497-516, pis. 1, 2. 1911. North Pacific ophiurans in the collection of the U.S. National Museum. U.S. Nat. Mus. 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Hawaiian and other Pacific Echini. The Echinoneidae, Nucleolitidae, Urechinidae, Echinocorythidae, Calyranidae, Pourtalesiidae, Palaeostomati- dae, Aeropsidae, Palaeopneustidae, Hemiasteridae, and Spatangidae. Mem. M.C.Z., vol. 46, March, no. 2, 203 pp., 18 pis. u The habits and reactions of a comatulid, Tropiometra carinata. Carnegie Inst., Washington, Publ. 251 August, pp. 111-119. Reports on the scientific results of the expedition to the Tropical Pacific, 1899-1900. XVIII. Reports on the scientific results of the expedition to the Eastern Tropical Pacific 1904-1905. XXX. Ophiuroidea. Bull. M.C.Z., October, vol. 61, no. 12, 28 pp., 5 pis. 1918. Report on the Crinoidea and Echinoidea collected by the Bahama Expedition from the University of Iowa in 1893. Bull. Lab. Nat. Hist. Univ. Iowa, April, vol. 7, no. 5, pp. 3-37, pis. 1-5. Brittle stars, new and old. Bull. M.C.Z., October, vol. 62, no. 265-338, 8 pis. 1919. Review of Walter Fisher's "Starfishes of the Philippine seas and adjacent waters." Science, October 10, n. s. vol. 50, pp. 348-350. (^jThe distribution of the littoral echinoderms of the West Indies. Carnegie Inst., Washington, Publ. 281, November, pp. 49-74, pis. 1-3. 1920. Reports on the scientific results of the expedition to the Eastern Tropical Pacific, in charge of Alexander Agassiz, by the U.S. Fish Commission Steamer "Albatross" from October 1904 to March 1905, Lieut. Commander L. M. Garrett, U.S.N., commanding. XXXII. Asteroidea. Mem. M.C.Z., Februar}', vol. 39, no. 3, 46 pp., 6 pis. Echinoderms in birds' stomachs. Science, June 11, n. s. vol. 51, pp. 594-595. Reports on the scientific results of the expedition to the Tropical Pacific, in charge of Alexander Agassiz, by the U.S. Fish Commission Steamer "Albatross" from August 1899 to March 1900, Commander Jefferson F. Moser, U.S.N., commanding. XXII. Reports on the scientific results of the expedition to the Eastern Tropical Pacific, in charge of Alexander Agassiz, by U.S. Fish Commission Steamer "Albatross," from October 1904 to March 1905, Lieut. Commander L. M. Garrett, U.S.N., commanding. XXXIII. Holothuroidea. Mem. M.C.Z., September, vol. 39, no. 4, 40 pp., 4 pis. 1921., The echinoderm fauna of Torres Strait: its composition and its origin. Carnegie Inst., Washington, Publ. 214, January, vol. 10, 223 pp., 40 pis. Report on the Echinoidea collected by the Barbados-Antigua Expedition from the University of Iowa in 1918. Univ. Iowa Studies, Nat. Hist., 15, March, vol. 9, pp. 103-121, pis. 1, 2. Vll 1922. With Austin Clark. Results of the Hudson Bay Expedition, 1920. III. The echinoderms. Contr. to Canad. Biol. n. s. 1, pp. 21-25. The holothurians of the genus Stichopus. Bull. M.C.Z., February, vol. 65, no. 3, 38 pp., 2 pis. Review of Mortensen's "Studies of the development and larvel forms of echinoderms." Science, April 21, n. s. vol. 55, pp. 431-433. ^The echinoderms of the Challenger Bank, Bermuda. Proc. Am. Acad. Arts ^'and Sci., June, vol. 57, no. 13, pp. 353-361, pi. 1. 1923. The echinoderm fauna of South Africa. Ann. So. African Mus., May, vol. 13, pp. 221-435, pis. 8-23. The distribution and derivation of some New England echinoderms. Am. Nat., May-June, vol. 57, pp. 229-237. Some echinoderms from West Australia. Jour. Linn. Soc. London, June 5, vol. 35, pp. 229-251, pi. 13. Two new genera of sea-urchins. Bull. M.C.Z., July, vol. 65, no. 10, 10 pp. Echinoderms from Lower California, with descriptions of new species: supplementary report. Bull. Am. Mus. Nat. Hist., October 5, vol. 48, pp. 147-163. 1924. Some holothurians from British Columbia. Canad. Field Nat., March, vol. 38, pp. 54-57. The holothurians of the Museum of Comparative Zoology. The Synaptinae. Bull. M.C.Z., June, vol. 65, no. 13, 46 pp., 12 pis. Echinoderms from the South African fisheries and marine biological survey. Pt. 1. Sea-urchins (Echinoidea). Fish, and mar. biol. surv. Union South Africa, September 10, 1924. Rep. 4, Spec. Rep. 1, pp. 1-16, pis. 1-4. 1925. A catalogue of the recent sea-urchins (Echinoidea) in the collection of the British Museum (Natural History). London, 1925, 28, 250 pp., 12 pis. Some sea stars from the Riksmuseum, Stockholm. Arkiv for zoologi, Novem- ber 16, vol. 18A, no. 8, pp. 1-8. A new Clypeaster from Angola. Ann. So. African Mus., December, vol.20, pp. 317-318, pi. 33. 1926. Echinoderms from the South African fisheries and marine biological survey. Pt. 2. Sea Stars (Asteroidea). Rep. 4, Spec. Rep. 7, Fish and mar. biol. surv. Union So. Africa, May 1, pp. 1-34, pis. 1-7. Echinoderms other than sea stars of the Tropical Central Pacific. Bull. 27, Bernice P. Bishop Mus., July, pp. 89-112, pis. 9-11. Notes on a collection of echinoderms from the Australian Museum. Rec. Austr. Mus., November 18, vol. 15, pp. 183-192. 1927. With B. W. Arnold. Jamaican fossil Echini. Mem. M.C.Z., October, vol. 50, no. 1, pp. 1-84, (errata sheets), pis. 1-22. Review of Mortensen's ''Handbook of the echinoderms of the British Isles." Science, December 23, n. s. vol. 66, pp. 625-626. 1928. The sea lilies, sea stars, brittle stars, and sea-urchins of the South Australian Museum. Rec. So. Austr. Mus., May 9, vol. 3, no. 4, pp. 361-482, text figs. 108-142. 1929. A new Miocene echinoid from California. Trans. San Diego Soc. Nat. Hist., August 5, vol. 5, no. 17, pp. 259-262. 1930. The Carnegie-Australia Harvard Expedition to Northwestern Australia. Science, February 21, n. s. vol. 71, p. 180. 1932. Echinodermata (other than Asteroids). British Museum (Natural History) Great Barrier Reef Expedition, 1928-1929. Scientific Reports, vol. 4, no. 7, pp. 197-239, 9 text figs., 1 pi. The ancestry of the Echini. Science, December 23, vol. 76, no. 1982, pp. 591-593. vm 1933. A handbook of the littoral echinoderms of Porto Rico and the other West Indian Islands. Sci. Survey, Porto Rico and Virgin Islands, N. Y. Acad. Sci., vol. 16, no. 1, pp. 1-147, 7 pis. Marine collecting in Australia. Harvard Alumni Bull., June 2, vol. 35, no. 32, pp. 901-906. 1934. With B. W. Arnold. Some additional fossil Echini from Jamaica. Mem. M.C.Z., December, vol. 54, no. 2, pp. 139-156, pis. 1-5. 1935. Some new echinoderms from California. Ann. Mag. Nat. Hist., January, ser. 10, vol. 15, no. 85, pp. 120-129. The holothurian genus Caudina. Ann. Mag. Nat. Hist., February, ser. 10, vol. 15, no. 86, pp. 267-284. 1936. With Elisabeth Deichmann. On Psolicucumts Heding and its allies. Ann. Mag. Nat. Hist., May, ser. 10, vol. 17, no. 101, pp. 564-568. 1937. A new Eocene sea-urchin from Alabama. Jour, of Paleontology, April, vol. 11, no. 3, pp. 248-249, 3 figs. The echinoid name Diadema. Ann. Mag. Nat. Hist., December, vol. 20, ser. 10, no. 120, pp. 635-636. A new sea-urchin from the "Oligocene" of Oregon. Trans. San Diego Soc. Nat. Hist,, December 15, vol. 8, no. 28, pp. 367-374, pi. 24. 1938. Echinoderms from Australia, an account of collections made in 1929 and 1932. Mem. M.C.Z., vol. 55, 596 pp., 28 pis., 64 text figs. List of Bahama echinoderms. (In W. J. Clench's report) Bull. M.C.Z., June, vol. 80, no. 14, pp. 536-537. 1939. Two new ophiurans from the Smithsonian-Hartford Expedition, 1937. Proc. U.S. Nat. Mus., May, vol. 86, no. 3054, pp. 415-418, pi. 52. A remarkable new genus of sea-urchin (Spatangidae). Allan Hancock Pacific Expeditions, vol. 2, no. 11, pp. 173-176, 2 text figs. Ophiuroidea. The John Murray Expedition, 1933-1934. British Museum (Natural History) Scientific Reports, October 28, vol. 6, no. 2, pp. 29-136, 62 text figs. A new Astroconus from South Australia. Rec. So. Austr. Mus., December 16, vol. 6, no. 3, pp. 207-208, pi. 18. 1940. Notes on echinoderms from the west coast of Central America. Zoologica, November 14, vol. 25, pt. 3, pp. 331-352, figs. 1-4, pis. 1-2. ^^evision of the keyhole urchins (Mellita). Proc. U.S. Nat. Mus., December, vol. 89, no. 3099, pp. 435-444; pis. 60-62. 1941. The echinoderms (other than holothurians). Reports on the scientific results of the Atlantis expeditions to the West Indies. Mem. Soc. Cubana Hist. Nat., May, vol. 15, no. 1, pp. 1-154, pis. 1-10. 1942. The echinoderm fauna of Bermuda. Bull. M.C.Z., April, vol. 89, no. 8, pp. 367-391, 1 pi. 1945. Echinoidea in "Geology of Lau," Fiji, by Ladd and Hoffmeister. Bull. 181, Bernice P. Bishop Mus., pp. 312-328, pis. 41-43. 1946. t^he echinoderm fauna of Australia, its composition and its origin. Carnegie Inst., Washington, December, Publ. 566, 567 pp. 1948. A report on the Echini of the warmer Eastern Pacific, based on the collections of the Velero HI. Allan Hancock Pacific Expeditions, vol. 8, no. 5, pp. i-xii, 225-351, pis. 35-71. IX PREFACE Mrs. H. L. Clark and her family have done me the great honour of asking me to edit my late friend H. L. Clark's Report on the Echini of the Warmer Eastern Pacific collected by the Velero III. In so doing I have thought it a holy duty towards my dear colleague and friend through- out nearly half a century to let his report appear in the main as it was intended by him, adding only some few remarks here and there, which I have deemed necessary. Only in his dealing with the genus Encope a more serious correction has been introduced. It was the idea of Clark that the genus ought to be divided in two separate genera, the species grandis to form a genus of its own in contradistinction to all the other species. This is in my opinion quite unacceptable. The only difference is that grandis is thicker and somewhat heavier than the other species ; but whether the edge of the test is 5 mm or only 2-3 mm thick is certainly not a morphological difference of generic value, and there are no other differences ; especially it should be emphasized that the internal structure of the test is exactly the same as in the other species. Moreover, separating grandis as a distmct genus from all the other species would necessitate most regrettable nomen- clatorial changes. His idea that the species emarginata would be the geno- type of Encope is decidedly erroneous. When establishing the genus Encope L. Agassiz (1840) named only a single species, grandis; accord- ingly grandis is the genotype of Encope. In one of his last letters to me Clark said that he would abide at the decision which I would make in this question. I wrote him at once that there could be no question at all but that grandis is the genotype of Encope, and he would certainly have changed his manuscript in accordance herewith; but he did not get the time to do so. I have thus had to change that part of his manuscript. As for the numerous new species of Encope which he establishes I think he is going much too far, small individual or local variations of this pro- lific genus being taken to represent distinct species. A few specimens (one of each species, and some of them too young to be of any use) sent me by Professor McCulloch do not at all convince me of the value of all his species; but without having access to the rich material on which Clark based his various species it is impossible for me to decide which of his Encope species are of real value and which are not. I deem it therefore our duty to publish them all, as Clark meant to have it done. It must then XI be left to posterity to solve definitely the question of the species to be distinguished within the forms belonging to the circle of — especially — Encope rnicropora. I cannot help also thinking how many species Clark, on the base of the study of a similar rich material of the Caribbean Encope emarginata might have made out of that polymorphic species. I hope that by the itw corrections and additions introduced in this manuscript I am doing justice to my late, lamented friend, the eminent echinologist, Hubert Lyman Clark. Copenhagen, in April 1948. Th. Mortensen xu REPORTS ON THE COLLECTIOKS OBTAINED BY ALLAN HANCOCK PACIFIC EXPEDITIONS OF VELERO III OFF THE COAST OF MEXICO, CENTRAL AMERICA, SOUTH AMERICA, AND GALAPAGOS ISLANDS IN 1932, IN 1933, IN 1935, IN 1936, IN 1937, IN 1938, IN 1939, IN 1940, AND IN 1941. A REPORT ON THE ECHINI OF THE WARMER EASTERN PACIFIC, BASED ON THE COLLECTIONS OF THE VELERO III (Plates 35-71, Text Figures 1-3) By HUBERT LYMAN CLARK The University of Southernj California Publications Allan Hancock Pacific Expeditions Volume 8, Number 5 Issued December 29, 1948 The University of Southern California Press Los Angeles, California A REPORT ON THE ECHINI OF THE WARMER EASTERN PACIFIC, BASED ON THE COLLECTIONS OF THE VELERO III (Plates 35-71, Text Figures 1-3) Hubert Lyman Clark The great collections of Echini (28,835 specimens, including over 11,000 young Dendr asters) made by the Velero III under the direction of Captain Allan Hancock, during the years 1931-1941, have proved a field for research as varied and interesting as it is large and illuminating. It was just eighty years ago that Verrill published his first papers on the Echinoderms of Panama and the w^estern coast of America and for four years he continued his studies of that fauna. In 1871 there appeared (Trans. Conn. Acad. vol. 1, pt. 2, art. 5, no. 8, pp. 593-595) his list of the Echini of the Gulf of California which included 22 species. Subsequent additions and emendations enabled A. Agassiz in 1904 to list 28 species from the Panamic region and 21 more from very deep water (300-2200 fms). In recent years additional species have now and then been added or corrections made, so that Grant and Hertlein (1938) include some 47 recent species in their list. Several, however, are from veiy deep water and are hardly to be counted in the present fauna of the warmer Eastern Pacific. The area thus designated may be defined as extending from the coast of Oregon at Ocean Park (Lat. 44° 50' 45'' N), southward along the American coast to San Juan Bay, Peru (Lat. 15° 20' S), and westward to include the islands, Socorro, Clarion, Cocos, and the Galapagos, down to depths of 80 fms or less, very rarely to 300-400 fms. In depths exceeding 100 fms, the water is no longer warm and the bottom fauna can not be properly included as belonging to the "waraier Eastern Pacific." The great gulf of California has an interesting fauna including 22 species of Echini. Only one of these, however, is restricted to the Gulf, 8 extend their range to the north and 19 to the south. Due to certain local restric- tions, collecting along the coast of Mexico and Central America did not yield so large a number of Echini as did the Gulf, and even in the Bay of Panama only 18 species were taken. Colombia yielded but 1 1 species while Ecuador has 14 to her credit and only 6 were recorded from Peru. North of the international boundary (United States-Mexico) some 14 species have been taken by the Velero. The outlying islands have proved good collecting grounds, for while Cocos yielded only 11 species, Clarion had 10, Socorro 12, and the Galapagos no few than 23, of which 4 were not found elsewhere. [225] 226 ALLAN HANCOCK PACIFIC EXPEDITIONS VOL. 8 The five visits of the Velero to the Galapagos, occupying 245 stations, have undoubtedly served the purpose of making the Echinoderm fauna of that group sufficiently well known to warrant the belief that it is essentially American and has not received any considerable influx of Indo-Pacific forms. Several of the species are, so far as we now know, endemic and warrant a belief in the long-sustained isolation of the marine fauna. In view of this it is worth while to list here the Galapagos Echini with a few words as to their occurrence : Eucidaris Thouarsii Hesperocidaris panamensis Centra cidaris Doederleini Centrechinus mexicanus Centrostephanus coronatus Lytechinus semituberculatus Toxopneustes roseus Tripneustes depressus Caenocentrotus gtbbosus Echinometra oblonga VanBrunti Clypeaster elongatus europacificus ochrus rotundus Encope galapagensis Cassidulus pacificus Agassizia scrobiculata Brissopsis pacifica generally Panamic and western Mexico Cocos Island, Galapagos Islands and Ecuador Cocos and Galapagos Islands generally Panamic, Mexico and Galapagos Islands generally Panamic, Gulf of Cali- fornia, southern California Galapagos Islands Panamic, Socorro Island Panamic, Mexican Islands Ecuador, Peru and Galapagos Islands Indo-Pacific to Northern Galapagos Islands and Mexican Islands Panamic, Western Mexico Galapagos Islands Panamic, Western Mexico Panamic Panamic, Western Mexico Galapagos Islands Panamic, Mexican Islands Panamic, Gulf of California Panamic, Western Mexico, southern California NO. 5 CLARK : ECHINI OF WARMER EASTERN PACIFIC 227 Idiobryssus coelus Galapagos Islands Meoma grandis Panamic, Western Mexico Gonimaretia laevis southern California and Gulf of California Lovenia cordiformis Panamic, Western Mexico, southern California Aside from the light thrown on the distribution of the known Echini in the Eastern Pacific, the Velero has collected an abundance of material useful in delimiting the known species, and revealing the existence of 11 forms which appear to require names as they do not fit too well into the series of species now known. One of these is a Cidarid and one a Clype- aster, but others are Scutellids of the well-known genera Dendraster and Encope. Never before have such large numbers of specimens been avail- able for comparative study, and it is not strange that new and perplexing forms occur which require designation. Quite likely more material from the coasts of southern Mexico, Costa Rica, Nicaragua, and Panama will indicate different and more correct grouping, but it is believed that the specific limits here suggested indicate a step forward in our knowledge of these multiform genera. The naming and describing of new species, however, is only one prod- uct of the Velero's extraordinary collecting. Equally important is the accumulation of immature and very young individuals showing stages in the development of the adult which throw light on evolutionary processes. The most striking of these is exhibited in the growth changes of young Spatangus, a genus represented by but one species in the Eastern Pacific, widely separated from its congeners in Europe, Asia and Africa. The Velero first met with Spatangus in 1936 in the Gulf of California but later collections showed that the vicinity of the Channel Islands in depths of 35- 225 fms is the real home of this interesting sea-urchin. Considerably more than two hundred specimens are in the collection and quite a number are young, including some very early stages of development, only about 3 mm long. In these very small individuals there is no indication of either petals or pores. When the individuals are 8 or 9 mm long the petals are indi- cated by more definite outlines and slight depressions, but there are no pores. After the length exceeds 10 mm, the petals can be distinguished more or less definitely and pores are visible at the apical end of the ambu- lacra. But the pores are single and the petals evidently are not sunken at all. There is thus a Palaeotropus stage of development shown which is usually passed through before the Spatangus is 12 mm long. In some 228 ALLAN HANCOCK PACIFIC EXPEDITIONS VOL. 8 cases, however, the growth changes are retarded and one individual caused much perplexity as it is 20 mm long and still reveals only single pores in the petals and hence was regarded as a new species of Palaeotropus. But the discovery of intermediate stages, showing all steps from poreless plates to normal twin-pored petals has been convincing in the demonstra- tion of this striking example of stages in development, so ably presented by Jackson (1899). For the opportunity to study this extraordinary collection, the writer is greatly indebted to Chancellor R. B. von KleinSmid of The University of Southern California and to Captain Allan Hancock and Professor Irene AlcCulloch of the Allan Hancock Foundation. Lieutenant Com- mander Fred C. Ziesenhenne, who played a major part in the collecting, preserving and arranging of the material, deserves high praise for the quality of his work. For thp pleasure of being his co-worker in the 1938 cruise of the Velero IIIj I am deeply indebted to Captain Hancock. That was one of life's great experiences and words are quite inadequate to express my appreciation. Finally I take pleasure in acknowledging the very great debt I owe to Mrs. Ora Willett for her patient assistance in the study of the collection and in the pi'eparation of the manuscript — assistance for which these few words of appreciation are quite inadequate. NO. 5 CLARK : ECHINI OF WARMER EASTERN PACIFIC 229 Order CIDAROIDA I Family Cidaridae Eucidaris Thouarsii (Valenciennes) Plate 35, Fig. 1 Cidaris Thouarsii L. Agassiz and Desor, 1846, p. 326. Cidaris (Eucidaris) Thouarsii Doderlein, 1887, p. 20. Eucidaris Thouarsii Mortensen, 1928a, pp. 393-400, pi. 42, figs. 5-13. There are, in the Hancock collections, more than 1,200 specimens from 175 stations. They range in size from 3.5 to 67 mm in diameter. The largest and finest specimens are from the Galapagos Islands, particularly Darwin Bay, Tower Island, and Cartago Bay, Albemarle Island. The character of the spines, both primary and secondary, shows extraordinary diversity. The secondaries range from relatively short, truncate spines to rather long ones tapering to a chisel-like tip. The primaries show even greater diversity ranging from short, stout spines with diameter .25-.30 of length to slender terete spines with greatest diameter less than a tenth of the length. There is great diversity also as to the extent to which the spines are covered with sponges, bryozoa or calcareous algae. Occasionally these foreign growths increase the diameter of the spine (at least at its base) to one-third of its length. In other individuals of the same size, from the same station, the spines may be entirely free from any foreign growth. The greater part of the Velero collection of Thouarsii is from the Galapagos Islands and a notable proportion of these individuals are larger and stouter than the material from the mainland coast. The specimens from Colombia, Panama, Costa Rica, and Mexico are on the whole smaller and have more slender spines than those from the islands. Occasional, sometimes conspicuous, exceptions prevent the drawing of any clear line ot distinction however. Mortensen's emphasis on the "nearly black" secondary spines in galapagensis is misplaced as most specimens from either mainland or islands have the secondaries a deep purplish brown, the shade apparently deepening with age. On the whole, it seems to me futile to try to maintain any well-defined form as a variety or subspecies galapagensis. Mortensen (1928, p. 399) has called attention to certain peculiarities in a specimen from Clarion Island which, if constant, would warrant recognition as at least a variety of Thouarsii. Unfortunately the present collection contains only a very few specimens from Clarion Island. While the largest of these seems to resemble the one studied by Mortensen, the others are not distingin'shable satisfactorily from specimens from the main- land coast. Further collecting at Clarion Island is greatly to be desired. Distribution. — This is one of the most characteristic sea-urchins of the western coast of tropical and subtropical America. E. Thouarsii occurs also at the outlying islands (Clarion, Socorro, Cocos and the 230 ALLAN HANCOCK PACIFIC EXPEDITIONS VOL. 8 Galapagos), but not at great depths. Mortensen reports it in 45 fms in the Gulf of Panama, while the Velero took specimens at depths of 62-76 fms of? Angel de la Guardia Island in the Gulf of California. The most northerly point from which it is reported is near Consag Rock in the Gulf of California. It is noteworthy that it has not been taken along the western coast of Lower California. Its southern limit, on the continental coast, is La Plata Island, Ecuador. It is very common among the Galapagos Islands where the Velero collected specimens at no fewer than 70 stations. Type. — Paris Museum? Type locality. — "Californie (Neboux.) Galapagos." Depth. — Shore to 76 fms. Specimens examined. — 1,201 specimens from 175 stations. Hesperocidarls panamensis (A. Agassiz) Plate 35, Fig. 2 Dorocidaris panamensis A. Agassiz, 1898, p. 73; 1904, p. 20, pis. 1-4. Hesperocidaris panamensis Mortensen, 1928, pp. 73-74; 1928a, Mon. Ech. p. 416. The material hitherto known of this sea-urchin consists of a few specimens taken by the Albatross in 1891 and now distributed in the U.S. National Museum, the Museum of Comparative Zoology and the British Museum. The Velero, however, has secured no fewer than 84 specimens, ranging from 4 to 49 mm in diameter ; the height of the test is about half as much or a little more; both the upper and lower surfaces are definitely flattened. The very young individuals are white orally but more or less light coral red above ; the primary spines are whitish with a tinge of red (at least basally) and have one or two ill-defined dusky bands and orange- red or flesh-red collar. In one specimen from the Galapagos Islands (Station 183-34) in 50-70 fms, the primaries are white except for more or less of the tip which is to some extent dusky or reddish ; the contrast between such primaries and the dull red secondaries is striking. With increasing size, however, the primaries become unicolor, gray or brown- ish, save for the collar, and rapidly increase in darkness until in adults, they are deep brown or brownish purple, except where more or less in- crusted with bryozoa, or other symbiotic forms. As a rule incrusta- tion is not extensive and the primaries are slightly flattened at the tip. In young specimens the collar tends to be conspicuously orange red, but with age the color deepens and in adults is dark red or even reddish purple of a very dark shade. The secondary spines are brownish red in small specimens but become dark, almost a deep blood red in adults. A full grown specimen is thus a very striking and rather handsome urchin. In some individuals the young primaries at the upper end of each series NO. 5 CLARK : ECHINI OF WARMER EASTERN PACIFIC 231 are uniformly more or less coral red in rather noticeable contrast to the older spines; this is particularly striking if the spine is entirely free from bryozoa or other incrustations. On the whole the coloration and general appearance of panamensis is remarkably uniform and makes the species easy to recognize. Distribution. — The most striking fact about the distribution of this Cidarid is that it has not yet been taken at Panama or anj^where else on the coast of North or Central America. The original specimens were from the vicinity of Cocos Island, and from 85-112 fms off Galera Point, Ecuador. The Velero material is all from Cocos Island and vicinity, where this handsome urchin is notably common in 30-50 fms, or from the Galapagos Islands where it was taken at eight stations in depths of 30-150 fms, chiefly in the vicinity of Albemarle Island. The station numbers are: 143-34, 147-34, 155-34, 171-34, 183-34, 190-34, 324-35, 325-35, 772-38, 773-38, 780-38 and 810-38. Type.— M.C.Z. no. 327 (Cotype). Type locality. — "Cocos Island and Galera Point, Ecuador." Depth.— ZOASQ fms. Specimens examined. — 84 specimens from 12 stations. Hesperocidaris perplexa (H. L. Clark) Plate 36, Fig. 3 Tretocidaris perplexa H. L. Clark, 1907, p. 205; pi. 6, figs. 1, 2; pi. 7, figs. 1-4. Hesperocidaris perplexa Mortensen, 1928, p. 421. Only five specimens of this near relative to panamensis were known hitherto, so that the large series of nearly 500 specimens in the Velero collections contribute all the information needed to verify the authenticity of the species and reveal such diversity as it shows. The specimens range from 5 mm in test diameter, with spines scarcely 5 mm long to large adults with the test 43 mm in diameter and 25 mm high, with primary spines 35-43 mm long. The flattening of the distal part of the large primary spines, on which Mortensen lays great stress, is not evident until the test is 30 mm or more in diameter and even then it is not conspicuous in most specimens. In the most extreme case at hand, the test is about 37 mm in diameter and the longest primaries are about the same ; the tips of ten or a dozen of these, at or above ambitus, are 3 to 5 mm wide ; the distal half of each of these widened spines is very rough with crowded, more or less sharp tubercles. In most specimens the primaiy spines are nearly cylindri- 232 ALLAN HANCOCK PACIFIC EXPEDITIONS VOL. 8 cal even at tip or somewhat terete, and are seldom noticeably rough. Their color is grayish or dull brownish but is frequently altered by bryo- zoa, sponges or other foreign growths. The striking and very constant feature of the coloration in perplexa is the conspicuous broad, brown longitudinal stripe which occurs on all the spinelets. The test itself is more or less yellowish or greenish but this shade is well shown chiefly, if not only, in the ambulacral mid-zones. The color of the basal part of the primary spines is commonly pale brown, usually greenish or yellowish just above the collar. The collar itself may have a more or less similar tint or may be more green, or yellow; in many specimens the general color of the spine is more or less dark brown, with the primary color flesh red or yellow brown. There is a great deal of variety in the shades of color in perplexa, some individuals being notably dark while many specimens, especially when young are definitely light. But no matter what the shades may be one feature of the coloration is remarkably constant and that is the longitudinal dark stripe found on all the secondaiy, and smaller, spines. Distribution. — Judging from the Velero collections, this Cidarid is particularly characteristic of the Gulf of California, having been taken at 16 stations, as far north as 29° 39'. Off the west coast of Lower Cali- fornia, there are no records, save one half grown specimen in poor condi- tion supposed to be from Station 1119-40, south of San Benito Islands, and a very young individual also in poor condition labeled as from Station 1153-40, off Santa Catalina Island, California. It is probable that these two specimens have in some way become mislabeled.^ South of Lower California, no specimens were taken save at Bahia Honda, Panama, (Stations 244-34, 863-38, and 948-39) in 30-50 fms, north of Gorgona Island, Colombia (Stations 854-38 and 855-38) in 10-60 fms, and off La Plata Island, Ecuador, (Stations 212-34, 213-34) in 7-55 fms. The entire absence of perplexa from the Galapagos area is worthy of note and even more remarkable is its absence from the vicinity of Cocos Island, where panamensis is common. Type.— M.C.Z. no. 188. Type locality. — Gulf of California. Depth. — 36-39 fms. Specimens examined. — 487 from 25 stations. 1 There are evidences in the studies of other groups that unexpected distribu- tional records are not uncommon. The work of the Velero III must be considered as the preliminary exploration of a coast involving many miles with little information concerning the fauna of the intervening areas. Ed. NO. 5 CLARK: ECHINI OF WARMER EASTERN PACIFIC 233 Hesperocidaris asteriscus-, new species Plate 36, Fig. 4; Plate 37, Figs. 5-6 Test somewhat flattened; vertical diameter about .60 of horizontal; coronal plates 6; areolae large, occupying most of plate surface; median interambulacral area narrow and fully covered with tubercles, smallest next to vertical suture which is quite indistinct; ambulacra about one-third of interambulacra in width ; poriferous zones rather wide and hardly at all sunken ; median ambulacral area narrow with a single row of relatively large tubercles on each margin and between these an irregular double series of much smaller tubercles which become more and more scattered and disappear entirely before the ocular plate is reached ; pores rather large, horizontal or slightly oblique, nearly circular. Abactinal system about .50 h. d., rounded pentagonal, clearly defined, the anal area somewhat ele- vated; each of the component plates and the anal area covered (save on the margins) with flat spinelets, the larger ones on the anal system with truncate or rounded tips, the others quite acute; the genital plates carry 30-35 spine-bearing tubercles, the ocular plates about 20; genital plates distinctly longer than wide and much wider at the inner end than at the slightly convex outer end ; ocular plates triangular, twice as wide as long, the margins slightly convex; both genital and ocular plates are bare, smooth and cinnamon color^ on the margins (excepting the distal margins of the oculars) so that the genital plates form a conspicuous star-shaped figure ; ocular plates all markedly excluded from the relatively large pen- tagonal anal system. Actinostome rather large, more than .40 h. d., not noticeably sunken, well covered with rather stout plates, which are hidden by the numerous spines they carry; these spines are long and narrow, with the distal end widened, rounded and curved inward very slightly. Primary spines longer than horizontal diameter of test, nearly cylindrical, fairly stout and blunt; they are densely covered with low, blunt tubercles in about a dozen more or less regular longitudinal series ; collar veiy narrow; secondary spines flat, only a little wider near the base than at the truncate slightly rounded tip ; miliary spines, few, very small, acute. No globiferous pedicellariae were found on any one of the specimens ; tridentate of two kinds, one with long narrow jaws, are abundant. In color, the test is pinkish cinnamon with the median ambulacral area distinctly light yellow- ish olive ; secondary and miliary spines brownish olive of diverse shades ; young primaries Japan rose or slightly darker, in some cases with one or 2 asieriscus^a little star, in reference to the star-like figure formed by the genital plates. 3 Color names are from Ridgway Color Chart as determined at the time of this study. 234 ALLAN HANCOCK PACIFIC EXPEDITIONS VOL. 8 two light bands near tip; mature primaries blackish brown except where covered by encrusting bryozoa or other organisms ; collar very low, verona brown; primary spines of oral surface light colored, those around the actinostome may be nearly white. The holotype is 26 mm h. d., 13 mm V. d. ; longest primaries 35 mm with a diameter near base of nearly 3 mm ; at tip, not quite two. Besides the holotype, there are two other Cidarids that must be re- ferred to this species, as they agree in all essentials. One is nearly as large as the holotype but is badly damaged on one side. The primaries of the oral surface show more red in their coloration and the secondaries are a lighter shade of brown. This specimen was taken with the holotype at Velero Station 948-39. March 28, 1939, off Medidor Island, Bahia Honda, Panama, in 30-35 fms on a bottom of mud, rocks and corallines, in com- pany with large numbers of perplexa. A third specimen, 15 mm in diameter with primaries 20-26 mm long, is supposed to be from Station 575-36, in the Gulf of California, but there is some doubt as to the reliability of the label. It is unquestionably conspecific with the specimens from Bahia Honda but shows much more red in the coloration and the primaries are not so black as in the holotype. The relationship of this species to perplexa is obvious, but to refer these specimens to that species would evidently be quite wrong. Type. — Holotype, AHF no. 46, 1 paratype. Type locality.— '^tzt.ion 948-39, of? Medidor Island, Bahia Honda. Panama, 30-35 fms, March 28, 1939. Distribution. — Type locality and the Gulf of California ( ?). Depth.— i(}-\00 ims (?). Specimens examined. — ^The type, paratype and one other specimen, from 2 stations. Gentrocidaris Doederleini (A. Agassiz) Plate 38, Fi^. 7 Goniocidaris Doederleini A. Agassiz, 1898, p. 73. Gentrocidaris Doederleini A. Agassiz, 1904, p. 33, pi. 14, figs. 1, 2. Apparently this is a verj^ rare urchin for, in all her collecting, the Velero has met with but one specimen — a small adult taken in the Galapa- gos Islands, near Barrington Island, in 48-73 fms. It is 24 mm in diameter and 13 mm high. The primaries are 20-28 mm long, exceedingly slender, and nearly cylindrical, either smooth or with low, well separated ridges. The abactinal system shows a star-like pattern, as in Hesperocidaris asteris- cus but in Gentrocidaris the lines are dark brown with light brown plates instead of the reverse. NO. 5 CLARK : ECHINI OF WARMER EASTERN PACIFIC 235 Distribution. — Cocos Island, Galapagos. Ty/)^.— U.S.N.M. No. 27348. Type locality: — Albatross Station 3369, off Cocos Island, 52 fms. Depth.— A^-ZOQ fms. Specimens examined. — 1 specimen. Order GENTRECHINOIDA Family Gentrechinidae Centrechinus mexicanus (A. Agassiz)* Plate 38, Fig. 8 Diadema mexicanum A. Agassiz, 1863, p. 20. Centrechinus mexicanus Ziesenhenne, 1937, p. 231. Diadema mexicanum Mortensen, 1940, p. 275, pi. 60, figs. 7-11. This big black sea-urchin, with long slender, acutely pointed and very poisonous spines, is a nuisance to bathers, beachcombers and fishermen throughout the tropical Eastern Pacific. Adult specimens are 70-80 mm in diameter with the height of the test about half as much. The primary spines may exceed twice the diameter of the test but they are so very fragile that it is extremely difficult to preserve specimens with the spines unbroken. The secondary spines are very slender and acicular but not very long; when they dry they are so fragile they are easily broken and lost. The absence of spines on the peristome is a constant and striking feature. Full grown individuals are virtually unicolor, black or very dark brown; occa- sionally definitely brown specimens occur. As in all the species of Centre- chinus (or Diadema) very young specimens have the long spines prettily banded with white and some dark shade, usually purple, but the white is sometimes tinged with brown and the purple is nearly black. With increas- ing size the white becomes more and more dingy and half grown specimens may have it entirely suppressed and the spines all uniformly dark. Banded spines in specimens half grown or more are common but usually only a few of the primaries show it. The poisonous character of the spines is well known and those who have once suffered the pain which even a single spine can cause, are forever after extremely careful in the vicinity of Centrechinus. Distribution. — This species was taken by the Velero at 38 stations, of which the most northern was at Consag Rock in the Gulf of California, the most southern at Gorgona Island, Colombia. The absence of specimens from the western coast of Lower California is notable, since the urchin occurs at both Socorro and Clarion Islands. It is also found at Cocos Island and throughout the Galapagos Islands. It is definitely a shallow water echinoid, for, although it was taken in 40-57 fms at the island, along *Please see explanation on p. 243. 236 ALLAN HANCOCK. PACIFIC EXPEDITIONS VOL. 8 the mainland coast nearly all the specimens at hand were taken along shore, very rarely in more than 2 fms. Type.— M.C.Z. no. 635 (Cotype). Type locality. — ^Acapulco, Mexico. Depth. — Shore to 57 fms. Specimens examined. — 191 specimens from 38 stations. Astropyga pulvinata (Lamarck) Plate 39, Fig. 9 Cidarites pulvinata Lamarck, 1816, p. 59. Astropyga pulvinata L. Agassiz and Desor, 1846, p. 345. Mortensen, 1940, p. 197, pis. 20-23. One of the characteristic Echini of the warmer Eastern Pacific, this handsome sea-urchin is well represented in the Velero collections. There are altogether 165 specimens, ranging in size from 5 mm h. d. with primary spines 7 mm long, to adults 100-117 mm in diameter. The diversity of color is very striking but is brightest in the young which are often very handsome and dullest in the adults. The largest specimen in the present collection is dry and measures 117 mm h. d. and about 40 mm v. d. It is uniformly dark (almost black) above save for the usual large triangu- lar interradial spots which are light buff but were probably white in life. Apparently this represents the form collected by Mortensen at Contadora Island, Panama, which he designates as variety venusta Verrill. The present specimen was taken in 15-20 fms in Tangola Tangola Bay, Mexico, in company with 3 specimens 70-90 mm h. d. which are all tjTical, handsomely variegated pulvinata, as are many other Mexican spec- imens. A very fine specimen, however, from Tiburon Island, Gulf of California, 10 fms, is almost completely dark violet above, the interradial spots being scarcely distinguishable and the lower surface being very markedly suffused with violet. This is the most heavily pigmented speci- men in the collection though only about 90 mm h.d. Young specimens (17-35 mm) from the Gulf of California, Panama, and Ecuador are verj' handsome in their variegated liveries of bright red, violet and yellow. It does not seem to me desirable to give varietal names to any of the varied forms, even though such extremes as venusta may be recognizable. Distribution. — This sea-urchin was taken by the Velero at some 16 stations along the Mexican and Central American coasts in depths down to 20 fms though many collections were made along shore. The northern- NO. 5 CLARK: ECHINI OF WARMER EASTERN PACIFIC 237 most Stations were at Tepoca Bay, Sonora, where only two very young specimens were taken and Tiburon Island, in the Gulf of California, in 16 fms, where 74 specimens were secured. The southernmost station was at Santa Elena Bay, Ecuador, in 8-10 fms, but no specimens were taken at either Cocos or the Galapagos Islands. Type. — Paris Museum ? Type locality. — "Habite — probablement les mers de I'Asie." Depth. — Shore to 20 fms. Specimens examined. — 165 specimens from 16 stations. Centrostephanus coronatus (Verrill) Plate 39, Fig. 10 Echinodiadema coronata Verrill, 1867, p. 295. Centrostephanus coronatus A. Agassiz, 1872a, p. 97. Mortensen, 1940, p. 314, pi. 36, figs. 7-10. Compared with the preceding two species, this is a relatively small sea-urchin, the largest known specimens being only 63 mm in diameter. The largest of the 131 specimens collected by the Felero are only 45-50 mm with the primary spines about twice as much. As the spines are very brittle, especially when dry, few specimens (even in the Vetera collec- tions, notable for the fine condition of typical specimens in nearly every species) show the handsome appearance of this sea-urchin in life. As in Centrechinus the spines are finely verticillate and very acute but there is no evidence that they carry poison at the tip as do those of Centrechinus. A veiy interesting character of this Centrostephanus is the presence on the uppermost interambulacral plates of short claviform spinelets the tips of which are bright red purple. This color persists in most preserved specimens but may be much duller and hence less noticeable than in life. Mortensen discovered that these spinelets are never resorbed or replaced by the long primary spines but the latter grow up around them and en- close them without resorption. Young individuals of this Centrostephanus are so similar to young examples of Centrechinus mexicanus that they are often confused with them but there are three characters by which the two species may be readily distinguished. The most important of these is the presence of these brightly tipped claviform spinelets in Centrostephanus which are never present in Centrechinus. A second distinctive character is the presence of slender, blunt, light-colored spinelets on the five pairs of oral plates around the mouth (in Centrechinus these plates may have pedicellariae but never spinelets). The third difference is in the color of 238 ALLAN HANCOCK PACIFIC EXPEDITIONS VOL. 8 PLATE 35 Fig. 1. Eucidaris Thourasii (Valenciennes), aboral view, x%, p. 229 Fig. 2. Hesperocidaris panamensis (A. Agassiz), aboral view, x%, p. 230 PLATE 36 Fig. 3. Hesperocidaris perplexa (H. L. Clark), aboral view, x%, p. 231 Fig. 4. Hesperocidaris asteriscus, new species, lateral view, x%, p. 232 NO. 5 CLARK : ECHINI OF WARMER EASTERN PACIFIC PL, 35 PL. 36 ALLAN HANCOCK PACIFIC EXPEDITIONS VOL. 8 NO. 5 CLARK: ECHINI OF WARMER EASTERN PACIFIC PL. 37 -f^^i 6 PL. 38 ALLAN HANCOCK PACIFIC EXPEDITIONS VOL.8 NO. 5 CLARK : ECHINI OF WARMER EASTERN PACIFIC 243 PLATE 37 Fig. 5. Hesperocidaris asteriscus, new species, aboral view, xYz, P- 232 Fig. 6. Hesperocidaris asteriscus, new species, oral view, x% PLATE 38 Fig. 7. Centrocidaris Doederleini (A. Agassiz), aboral view, xl, p. 234 Fig. 8. Centrechinus mexicanus (A. Agassiz),* oral view, xj4) p. 235 *In a recent letter from Th. Mortensen he states that The International Com- mission on Zoological Nomenclature meeting in Paris this summer (1948) rendered an Opinion which codified the name Diadema as a nomen conservandum. This species is, therefore, Diadema mexicanum A. Agassiz, order Diadema- toidea, family Diadematidae. These corrections replace corresponding names used on p. 235 of the text. 244 ALLAN HANCOCK PACIFIC EXPEDITIONS VOL. 8 the primary spines; in young Centrechinus the spines are banded bluish or purplish and white, in Centrostephanus dull purplish brown and light yellow. With increasing age and size, the colors become duller until the mature primaries are uniformly black in Centrechinus, dark brown in Centrostephanus. It is unusual for banded spines to be evident in adults of either genus but carefully preserved alcoholic specimens of Centro- stephanus, even when full grown, commonly show the banding on some primaries at least, though faintly. Most dry specimens, however, appear to be more or less uniformly dark brown or quite black. On the contrary, very young specimens (less than 10 mm in diameter) are unusually pretty objects, the test and small spines deep brown, the dull yellow primaries more or less evidently banded with purplish brown, and five or more claviform spinelets, with bright rose-purple tips around the apical system. Distribution. — This species of Centrostephanus is definitely a shallow water Mexican sea-urchin but the Velero took it at five stations in the Galapagos Islands. At Albemarle Island it was found in shallow water but ofif James Island it occurred in 36-60 fms. It was not met with at either Cocos or the more northern islands (Socorro and Clarion), or on the west coast of Lower California. Yet it is frequently found at Newport and Corona del Mar, California, near low water mark. It has yet to be taken on the mainland coast south of the Gulf of California but in the Gulf it has been found as far north as Rocky Point, Sonora, and Consag Rock, in depths down to 45 fms. Type. — Peabody Museum, Yale University, no. 964. Type locality. — Cape San Lucas, Lower California. Depth. — Shore to 60 fms. Specimens examined. — 131 specimens from 37 stations. Family Arbaciidae Arbacia incisa (Blainville;? Gmelin) Plate 40, Fig. 11 Echinocidaris incisa A. Agassiz, 1863, p. 20. Arbacia incisa H. L. Clark, 1913, p. 220. Arbacia stellata Mortensen, 1935, p. 575, pi. 70, figs. 6-9. This is one of the commonest sea-urchins of the Gulf of California and was taken by the Velero at many stations there. Along the coast southward it seems to be less common and relatively few specimens were secured but unmistakable examples were collected as far south as Peru. Indeed one of the largest specimens in the collection, 47 mm h.d., was taken nine miles south of Zorritos Light, in shore collecting; from tip to NO. 5 CLARK : ECHINI OF WARMER EASTERN PACIFIC 245 tip of the extended spines it measures 120 mm. Mortensen refers to the "largest size recorded for this species is 60 mm diameter" but he does not give his authority for this giant.^ Only a very few of the Velero's 1,121 specimens exceed 35 mm h. d. (the largest is 56) and a very large number are less than 20 mm across. Veiy young specimens (2-8 mm h. d.) are as a rule light colored more or less flesh red, becoming red brown, or violet or deep purple, until finally they are nearly or quite black. A few dry specimens are more or less definitely gray. One curious variety has some of the primaries, or at least portions, quite pink or white in striking con- trast to the black of the remaining spines and test. Mortensen (p. 566) makes the "conspicuous red spots in the interambulacra on the aboral side" the distinguishing mark of the species and the Velero collection con- firms his judgment. Even in the most nearly black adults, careful examin- ation in good light will show at least faint indications of the tell-tale red blotches. Young individuals with the test flesh color or red and the red spines with one or more whitish bands are so different from the more mature specimens, it is hard to believe they can ever become as dark colored as they do, but the present large series compels the acceptance of the fact. In one or two of the very black specimens there is real difficulty in seeing any red, but such individuals cannot be distinguished satis- factorily as anything other than excessively pigmented incisa. Mortensen's (1935, p. 577) plea for the specific name stellatus is inadequate, and if we once let such arguments control our decisions we shall have more disagreements and resulting confusion than we have had hitherto. Nobody knows to what sea-urchin the name stellatus was first given. Everyone knows what Echinocidaris incisa was at the start and there has never been any confusion about it, so I have no hesitation in continuing the use of the name here. Distribution. — The Velero collections show that this is essentially a species of the Gulf of California. It ranges north to the southern United States as shown by Ziesenhenne (1941, pp. 117-120). There are 6 very fine adult specimens in the Velero collection from Newport Harbor, California, but the Velero has taken no other specimens north of Lower California, nor along its western coast. South of the Gulf, incisa does not appear to be very common though there are specimens at hand from Bahia Honda, Panama; Gorgona Island, Colombia; Santa Elena Bay and La Plata Island, Ecuador; Zorritos Light, South Bay, Lobos de Afuera, 4 The authority for this giant is Clark himself, who says in his Echinoderms of Peru, p. 345, that "large specimens may be 60 mm in diameter." Th. Mortensen 246 ALLAN HANCOCK PACIFIC EXPEDITIONS VOL. 8 and Middle Chincha Island, Peru. The last is the farthest south for incisa, 13° 39' 15" S. All stations are in shallow water, less than 50 fms and almost always less than 20, A very small specimen is labeled as from Station 1105-40 in the Gulf of California, with a depth of 113-127 fms. It is probable that this individual was actually dredged at Station 1101- 40, but was lost in the meshes of the dredge until the careful search after a deep water haul. It is notable that no specimens of incisa were taken at the Galapagos Islands, Cocos, Clarion or Socorro Islands, nor along the Costa Rican coast, though it has been previously recorded from the Galapagos. Type.— M.C.Z. no. 467 (Cotype). Type locality. — Guaymas, Lower California, Mexico. Depth. — Shore to 50 fms. Specimens examined. — 1,121 specimens from 82 stations. Arbacia spatuligera (Valenciennes) Plate 40, Fig. 12 Echinus (Agarites) spatuliger Valenciennes, 1846, pi. 5, fig. 2. Arbacia spatuligera A. Agassiz, 1872a, p. 93. H. L. Clark, 1910, p. 346, pi. 10, fig. 2. Mortensen, 1935, p. 577, pi. 70, figs. 1-5. Adult specimens of this rather handsome sea-urchin are said to reach a test diameter of 70 mm but the finest of the 15 specimens secured by the Velero are barely 50 mm h. d. and the longest spines scarcely exceed 40 mm. These large specimens (30-50 mm h. d.) are brown, very dark on the test but with the spines much lighter, a real fawn brown. Small speci- mens (15-25 mm h. d.) are dark; the smaller has the interambulacra definitely tinged with green and the spines are dull pink or rose, brightest on the lower surface; the larger (25 mm h.d.) has the dark interambula- cra scarcely tinged with green and the primary spines dark violet. A series of 5 very small Arbacias from Sechura and Independencia Bays, Peru, are pale gray or whitish or reddish brown, with the primary spines either colorless or with one or two light red bands. While it is not certain that these little Arbacias are young spatuligera, there is little reason to doubt it. Distribution. — Even including the very small Arbacias just men- tioned, the Velero material throws no new light on the distribution of spatuligera. The largest specimens are from San Lorenzo Island, Peru in 5 fms. The remaining material is from Sechura and Independencia Bays in water 10 fms deep or less. So far as the Velero collections are concerned this Arbacia is found only in Peru. NO. 5 CLARK : ECHINI OF WARMER EASTERN PACIFIC 247 Other records, however, extend its range to Ecuador and Chile. Type. — Unknown. Type locality. — "Carthagena on the west side of the Isthmus of Darien." (Panama) Depth. — Shore to 10 fms. Specimens examined. — 16 specimens from 6 stations. Tetrapygus niger (Molina) Plate 40, Fig. 13 Echinus niger Molina, 1782, p. 200. Tetrapygus niger A. Agassiz and H. L. Clark, p. 73. H. L. Clark, 1910, p. 345, pi. 10, f^g. 1. Mortensen, 1935, p. 582, pi. 70, figs. 10-12. This is one of the most characteristic of the sea-urchins of the South American Pacific coast for it is primarily a Peruvian species and has not yet been found north of the equator nor at the Galapagos Islands. The Velero collection contains 274 specimens. Over 250 of these were found along shore and are for the most part adult; few are less than 15 mm h. d. Only at Fronton Island, near Callao, in 5 fms, were specimens of niger dredged. The color of the adults is dull black; small specimens (under 25 mm) tend to be more brownish but not markedly so. South of Peru, niger ranges far down on the Chilean coast but its northern limit is near Payta, Peru. At the Lobos de Afuera Islands it is very common. Other authors include Chile and Patagonia in the range. Type. — Unknown. Type locality. — Chile. Depth. — Shore to 5 fms. Specimens examined. — 274 specimens from 9 stations. Family Echinidae Lytechinus anamesus H. L. Clark Plate 41, Fig. 14 Lytechinus anamesus Yi. L. Clark, 1912, p. 254, pi. 107, figs. 7-11. Mortensen, 1943, p. 452, pi. 23, figs. 33-40. Apparently the commonest sea-urchin in moderate depths off the southern California coast, this rather attractive small species was taken by the Velero at no fewer than 155 stations at depths of 8 to 160 fms. Alto- gether 5,090 specimens were secured, the largest 37 mm in diameter. When very young it is light colored, often quite white, more often cream 248 ALLAN HANCOCK PACIFIC EXPEDITIONS VOL. 8 color, but by the time it is 8-10 mm across, spots and blotches of gray or dull green have begim to appear and in mature specimens, 20-30 mm across, the upper surface may be more or less dull colored with spots or blotches of cream color. The slender, more or less acicular, spines are unicolor, generally cream color or even white, but the smaller ones are often graj'. In many specimens, however, the primary spines are yellowish brown or even rust color, and in others they are dull gray. From some stations the specimens are so dark as to be easily confused with pictus. This is most apt to be the case with material from the deeper water sta- tions, much of the test and most of the spines being dull greenish gray ; in such specimens the spines are apt to be shorter and blunter than usual, and the resemblance to the following species may be confusing. The dif- ferences will be emphasized under pictus. Very young specimens of anamesus are almost pure white or very pale yellow and the primary spines are often conspicuously long and acicular. Before the test is 10 mm in diameter, a dull colored spot begins to appear at the upper end of each interradial area and these are soon followed by others until in adult specimens the whole upper surface of the test is conspicuously blotched with the darker shade. At the same time primary spines also take on the dull color, in more or less marked contrast with their fellows. As already stated some individuals, and at some stations all, are so dark as to be difficult to recognize as anamesus. Occasionally individuals are met with of so dark a brown as to make identification difficult but the relatively long acicular spines are distinctive in most of such cases. Not rarely specimens 12-15 mm in diameter are met with which have developed no pigment but are uniformly white or cream color. As a rule, however, pigmentation begins vtry soon after the test is fully formed. Distribution. — ^The remarkably limited range of this sea-urchin is notable for the thousands of specimens taken by the Velero are convinc- ing proof that it is a very common species off the coast of southern Cali- fornia and the adjoining islands, as far south as Station 283-34 off Thurloe Head, Lower California (27° 37' 30'' N). It was not taken north of Station 1410-41 (34° 53' 35" N), 3 miles east of the southern point of Santa Rosa Island, in 17-20 fms. It was seldom taken in less than 20 fms, the least depth being in 8-10 fms, at the southernmost sta- tion, off Thurloe Head. The greatest depth was at 160 fms at Station 1182-40, near Catalina Island. This distribution is strikingly similar to that of the 414 specimens on which the species was based. The Albatross NO. 5 CLARK : ECHIXI OF WARMER EASTERN PACIFIC 249 took them at 25 stations between 28° 12' N and 34° 24' 30" N at depths of 20-113 fms, including Guadeloupe Island. Type.— U.S.N. M. No. 32660. Type locality. — Albatross Station 2930, off San Diego, 60 fms. Depth.~S-\6() fms. Specimens examined. — 5,090 specimens from 155 stations. Lytechinus pictus (Verrill) Plate 41, Fig. 15 Psammechintis pictus Verrill, 1867, p. 301. Lytechinus pictus H. L. Clark, 1912, p. 258, pi. 107, figs. 12-14. This species has undoubtedly been confused with the preceding and the suggestion has been made that the two are identical but show great diversity. The thousands of specimens of anamesus taken by the Velero are supplemented by some 488 specimens of pictus, ranging from 2 to 38 mm in diameter. When young the two species are so different they could not be confused but mature specimens may look veiy much alike. Young anamesus are pure white with long, acicular white spines. As they mature the color becomes more yellowish, and blotches of gray or dull purple appear on the upper side of the test, but there is no hint of red or violet on either test or spines. When adult, the slender, acute, unhanded spines are quite different from the relatively short, rather thick, blunt spines of pictus. In specimens of pictus less than 8 mm in diameter the primary spines of the oral side at least are definitely reddish, ranging from dull pink to a clear rose purple, with one or more definitely white bands. In some cases the bands are not evident but there is more or less red or rose purple evident on at least the distal part of the spines, but after the test is more than 10 mm in diameter the spines are unicolor, gray, brown or red purple. Often the basal half is nearly white, the distal half more or less dull rose or dull yellow. In young specimens there is usually rose purple or violet evident on the abactinal system but this soon disappears and the whole system becomes a dull gray. Young pictus with banded rose purple spines may be easily confused with young Strongylocentrotus purpuratuSj but in Lytechinus the color is much more pink than in pur- puratus. In anamesus there is never any pink or rose purple shade in the coloring of the spines but yellow, yellow brown or dull orange may be marked ; usually the shades are dull gray or olive when not yellowish or brown ; on the oral surface the spines are commonly white. In pictus there is usually no white on the oral side but some individuals are as white as any anamesus. 250 ALLAN HANCOCK PACIFIC EXPEDITIONS VOL. 8 PLATE 39 Fig. 9. /J stropyff a pul'vinata {Lamarck), ahoral view, X approx. Yz, p. 236 Fig. 10. Centrostephanus coronatus (Verrill), aboral view, x approx. H, p. 237 PLATE 40 Fig. 11. Arbacia incisa (Blainville, ? Gmelin), aboral view, x%, p. 244 Fig. 12. Arbacia spatuligera (Valenciennes), aboral view, x%, p. 246 Fig. 13. Tetrapygus niger (Molina), aboral view, x%, p. 247 PLATE 41 Fig. 14. Lytechinus anamesus H. L. Clark, aboral view, xl, p. 247 Fig. 15. Lytechinus pictus (Verrill), aboral view, xl, p. 249 Fig. 16. Lytechinus semituberculatus (Valenciennes), aboral view, xl, p. 261 PLATE 42 Fig. 17. Toxopneustes roseus (A. Agassiz), aboral view, xl, p. 262 Fig. 18. Tripneustes depressus A. Agassiz, aboral view, x%, p. 263 NO. 5 CLARK : ECHINI OF WARMER EASTERN PACIFIC PL. 39 PL. 40 ALLAN HANCOCK PACIFIC EXPEDITIONS VOL.8 XO. 3 CLARK: ECHINI OF WARMER EASTERN PACIFIC PL. 41 PL. 42 ALLAN HANCOCK PACIFIC EXPEDITIONS VOL.8 NO. 5 CLARK : ECHINI OF WARMER EASTERN PACIFIC PL. 43 PL. 44 ALLAN HANCOCK PACIFIC EXPEDITIONS VOL.8 NO. 5 CLARK: ECHINI OF WARMER EASTERN PACIFIC PL. 45 PL. 46 ALLAN HANCOCK PACIFIC EXPEDITIONS VOL.8 26 NO. 5 CLARK: ECHINI OF WARMER EASTERN PACIFIC 259 PLATE 43 Fig. 19. Loxechinus albus (Molina), aboral view, xl, p. 265 Fig. 20. Caenocentrotus gihbosus (L. Agassiz and Desor), aboral view, xl, p. 265 PLATE 44 Fig. 21. Allocentrotus fragilis (Jackson), aboral view, xl, p. 276 Fig. 22. Strongylocentroius purpuratus (Stimpson), aboral view, xl, p. 279 PLATE 45 Fig. 23. Strongylocentroius franciscanus (A. Agassiz), aboral view, x^o, P- 278 Fig. 24. Echinometra oblonga (Blainville), aboral view, xl, p. 281 PLATE 46 Fig. 25. Echinometra VanBrunti A. Agassiz, aboral view, x%, p. 293 Fig. 26. Clypeaster europacificus H. L. Clark, aboral view, x%, p. 294 260 ALLAN HANCOCK PACIFIC EXPEDITIONS VOL. 8 Aside from color and character of the spines, it is hard to find any very tangible differences between the two species. On the whole the number of coronal plates and of large tubercles is greater in pictus than in anamesus. Specimens 25 to 30 mm h. d. having about 20 interambula- cral plates in a column, have in pictus, 27 or 28 ambulacrals, in anamesus about 20 or 21. In the same specimens, pictus has 4 large primary tubercles on each coronal plate just below the ambitus, while in anamesus there are but 3 tubercles. Furthermore, the interambulacral areas above the ambitus obviously carry fewer tubercles in anamesus than in pictus. Mortensen ( 1943, pp. 437, 450) had no specimens of pictus available for critical study but saw Verrill's type and cotype at New Haven. He describes them as "light purple with radiating whitish bands, the spines bright purple, more or less distinctly banded." In all the hundreds of Lytechinus from the southern California coast, no specimen with any definitely purple tint has been seen. Neither has any individual with "spines bright purple, more or less distinctly banded" been detected. The difficulty is probably due to mis- understanding in the use of color terms. Mortensen 's "purple" is prob- ably what to me is "rose violet," but none of the Lytechinus at hand could by any possibility be called "bright" colored. Distribution. — The 42 stations at which pictus was taken by the Velero are widely scattered and show a perplexing distribution. Some of the best material has been secured at Newport, Balboa, and Corona del Mar, California, at or near low water mark and a few specimens have been taken at or near the Channel Islands in moderately deep water, 3-39 fms. But most of the specimens are from stations in the Gulf of California usually in rather deep water, 40-95 fms. Much further south some very small Echini have been taken which are best treated as pictus. Half a dozen were secured at La Plata, Ecuador, 7-10 fms, which may possibly be Mortensen's panamensis but their very small size prevented satisfactory determination. A single specimen from Gorgona Island, Colombia, in 20 fms and one from Bahia Honda, Panama, 5-8 fms offer the same difficulty. They may possibly be panamensis but it is not wise to assert that they are. Type. — Peabody Museum, Yale University, no. 961. Type locality. — "Cape San Lucas, California" (Grant and Hertlein, 1938, p. 25). Depth. — Shore to 95 fms. Specimens examined. — 488 specimens from 42 stations. NO. 5 CLARK : ECHINI OF WARMER EASTERN PACIFIC 261 Lytechinus semituberculatus (Valenciennes) Plate 41, Fig. 16 Echinus (Psammechinus) semituberculatus L, Agassiz and Desor, 1846, p. 368. Lytechinus semituberculatus VtrnW, 1867, p. 301. Mortensen, 1943, pp. 456-459, pi. 26, figs. 5,6. This well marked species is represented in the Velero collection by 863 specimens, but it should be stated at once that 570 of them are bare tests from a sand beach adjacent to lava rock at Bindloe Island, Galapagos Islands. The largest specimen at hand is 43 mm in diameter but most of them are considerably less than that. The yellow green color of the primary spines is very characteristic of well grown specimens, but very 3^oung individuals, 5 mm or less in diameter are bright vermilion red or paler, even a simple cream color with the median interambulacra apically deep green. Individuals 8-15 mm h. d. are often very handsome with the test deep green above and more or less pure white beneath ; the dorsal half of each interambulacrum may be deep red in sharp contrast with the ver- milion red and white of the ambulacra. The apical S5^stem in such speci- mens is greenish with a few vermilion red spots. In some young individuals the red may be very pale except orally, and in others it may be wholly wanting, the resulting green and white livery being soon replaced by the brownish test and long green spines of the adult. In youth the green shades are rich and rather dark and more or less mixed with white but with in- creasing size the white as well as the red tends to disappear. It is hard to believe that the really beautiful red, green, and white j'oung urchins can so soon and so completely lose their beauty and become the uniformly dull brown or blackish adult covered with uniformly yellow-green spines. Some adults have the spines tinged at the tip with yellow brown and rarely the color of a dried specimen may be definitely brown with little indication of green. In the great majority of museum specimens, however, the characteristic yellow green or light green shade of the primaries is unmistakable. Distribution. — This urchin is one of the most typical of Galapagos echinoderms. The Velero took it at 43 stations in the archipelago ; 10 times near Charles Island, 8 near James, 6 at Albemarle, 5 at Hood, 4 at Inde- fatigable, 3 near South Seymour, 3 at Barrington and one each at Bar- tholomew, Bindloe and Tower. Not a specimen has been secured at Cocos 262 ALLAN HANCOCK PACIFIC EXPEDITIONS VOL. 8 Island or anywhere along the American coast. Mortensen reports it "with full certainty" from Clarion Island^ but the Velero visited that isolated island twice and made 17 hauls of the dredge, besides two collecting trips along shore, and failed to find a single specimen. Certainly it should be found on the rich collecting ground at Cocos Island, if it occurs north of the Galapagos. If it is found on the American coast anywhere it is strange that the Velero has not met with it. It may be added that Dr. Coker did not find it on the Peruvian coast during his stay there (1907-1908) nor did the Templeton-Crocker Expedition secure any specimens at Clarion Island in 1936. There seems no adequate reason for doubting that this sea-urchin occurs only at the Galapagos Islands. Type. — Paris Museum. Type locality. — Galapagos Islands. Depth. — Shore to 73 fms. Specimens examined. — 863 specimens from 43 stations. Toxopneustes roseus (A. Agassiz) Plate 42, Fig. 17 Boletia rosea A. Agassiz, 1863, p. 24. Toxopneustes roseus ^lorttnstn, 1903, p. 111. Grant and Hertlein, 1938, p. 26, pi. 17, figs. 1, 2. Mortensen, 1943, p. 483, pi. 31, figs. 1-5. Not a very common sea-urchin of the Panamic region, this large and striking species was not often secured by the Velero; only in 1933-34, 1934-35, 1938 and 1939 were specimens taken. Of the 22 specimens at hand, 14 are from Panama, near Secas Islands, in 3 fms. Of the remaining 8, 3 are very small (15-23 mm in diameter) and only one is more than half grown. Even the smallest is easily distinguished by the relatively huge and commonly widely open globiferous pedicellariae. The extra- ordinaiy appearance of the living sea-urchin is admirably shown in Mortensen's figures of the closely related species, pileolus (1943, pi. 26, fig. 3 and pi. 27, fig. 2). No other sea-urchin gives any such display of pedicellarian power as does Toxopneustes. The western Pacific species of 5 The expression "with full certainty" quoted from my Monograph (p. 459) refers to the identification of the specimens of L. seinhuberculatus from Clarion Island mentioned by Clark in his catalogue of Recent Sea-Urchins in the Coll. of the British Museum, p. 120, the identification of other specimens being uncertain, as pointed out both by Clark and myself. The locality Clarion Island of the specimens in the British Museum may be erroneous. Th. Mortensen NO. 5 CLARK : ECHINI OF WARMER EASTERN PACIFIC 263 the genus are also interesting for their coloration which is notably varied and inconstant, but the Panamic species is unicolor, more or less rose or, according to Mortensen "light purple." Preserved specimens are dull yellowish brown or the test may show a definitely purplish tint. Very young specimens are yellowish, with spines and the big widely opened pedicellariae, white. So far as preserved material is concerned the name roseus is most inappropriate. Distribution. — The Velero took Toxopneustes at only 7 stations. The northernmost was at Port Culebra, Costa Rica, in 3-10 fms. The southern- most was at La Plata Isle, Ecuador, in 4 fms. The young specimens refer- red to above, 15-23 mm in diameter, were found at Port Utria, Colombia. A small adult was found at Braithwaite Ray, Socorro Island, in 20 fms and a somewhat larger individual was collected at Sulivan Bay, James Island, Galapagos Islands, at the same depth. This is the only record from the Galapagos Islands but there is apparently no doubt about either the locality or the identification. It is remarkable that Toxopneustes has not been taken on the Mexican coast or at Cocos Island. It is difficult to see why it does not occur north of Costa Rica but except for the Velero's specimen from Socorro Island and Mortensen's statement of its occurrence at La Paz, there are no records from the Mexican coast or islands. Neither the Velero nor the Templeton-Crocker Expedition found even one speci- men in the Gulf of California. Type. — No type. Type locality. — Acapulco, Mexico. Depth.— 2-30 fms. Specimens examined. — 22 specimens from 7 stations. Tripneustes depressus A. Agassiz Plate 42, Fig. 18 Tripneustes depressus A. Agassiz, 1863, p. 24. Mortensen, 1943, p. 498, pi. 35, figs. 1, 2; pi. 38, fig. 9. The largest regular sea-urchin of the western coast of tropical America this species reaches a horizontal diameter of 150 mm. There is great diversity in form, for while the height is usually a little more than half the diameter, the specimen 150 mm horizontally is only 72 mm vertically, and a specimen 138 mm across is only 65 mm high. On the other hand a specimen 127 mm across is 83 mm high. The height of the test thus ranges 264 ALLAN HANCOCK PACIFIC EXPEDITIONS VOL. 8 from 47 to 65 per cent of the diameter. Growth changes from 30 mm h. d. to 150 mm are chiefly in the number of secondary and miliary tubercles (and spines, of course). In the young individuals, there are two columns of primary tubercles in the ambulacra and two in the interambulacra, with secondary and miliary tubercles present between them in the interambula- cra in not veiy well-marked series. On the ambulacra there are few tubercles of any importance in the interporiferous area save for one column on each side. In an adult, 100 mm or more in diameter, there are 10-12 well-spaced columns of primarj^ tubercles and many well-scattered smaller tubercles in the interambulacra. The ambulacra have undergone a more marked change; 4-6 imperfect columns of primary tubercles occupy the interporiferous area, and the poriferous areas have themselves widened markedly and cany 3 or 4 columns of tubercles mixed with irregularly scattered tube-feet between an inner and outer column of tube-feet which sharply delimit the area. The scattered tube-feet are much more numerous on the inner side of the area than on the outer. As for color, the dry speci- mens are very unattractive, as they were obviously prepared in haste. The test is almost black but with purple tinge more or less evident, and the spines are pale brown or brownish-white. One small adult in alcohol gives a better idea of the color in life. The test is purple, lightest on the porifer- ous areas, darker and duller on the interambulacra and on the interporif- erous areas of the ambulacra. The spines are white in marked contrast to the test. Distribution. — The 63 specimens of depressus brought in by the Velero are, with only two exceptions, from outlying islands. The excep- tions are from the shores of Secas Islands, Panama. Of the other 61 speci- mens, 7 are from the Galapagos Islands (Albemarle, Tower, Chatham, Charles, and Gardner), all from along shore except the half grown speci- men from near Gardner Island which was dredged in 12 fms. Of the remaining specimens 43 are from Socorro and 11 from Clarion, all secured by collecting along shore. The type locality is said to be Guaymas, Mexico, but it is notable that neither the Velero nor the Templeton-Crocker Expedition found any Tripneustes in the Gulf of California nor on the Mexican coast. Type. — No type. Type locality. — Guaymas, Mexico. Depth. — Shore to 12 fms. Specimens examined. — 63 specimens from 10 stations. NO. 5 CLARK : ECHINI OF WARMER EASTERN PACIFIC 265 Family Strongylocentrotidae Loxechinus albus (IMolina) Plate 43, Fig. 19 Echinus albus Molina, 1782, p. 200. Loxechinus albus Desor, 1858, p. 136. Strongylocentrotus albus H. L. Clark, 1910, p. 347, pi. 12, fig. 1. This large sea-urchin of the western coast of South America is exten- sively used for food along the Chilean coast as Tripneustes is in the West Indies. In both cases it is the voluminous gonads which are eaten, com- monly roasted in the "half-shell." The largest specimen taken by the Velero is somewhat less than 100 mm h. d, but specimens 120 mm in diameter are reported. Altogether only 23 specimens were taken. The smallest is 16 mm in diameter, the largest 84. The parasitic crab, (Pinnaxoides), which so often lives in the periproct of this sea-urchin and the following, Caenocentrotus gibbosus, is evidently present in at least 9 cases. The color is pretty uniformly green in spite of being often more or less bronzed over with red-brown. In specimens less than 20 mm h. d. the tips of the spines may be quite red. But in none of the specimens that I have ever seen is there any obvious reason why the specific name albus should have been attached to this sea-urchin. Distribution. — The Velero met with this urchin only three times — first in 1935 along the shore in Independencia Bay, again in 1938 in San Juan Bay and Independencia Bay, and thirdly, a few days later further north, among the Lobos de Afuera Islands. This extends the range from the Lobos de Afuera Islands, northern Peru (6° 53' 50"), southward to the Straits of Magellan. Type. — Unknown. Type locality. — Chile. Depth. — Shore to 40 fms. Specimens examined. — 23 specimens from 6 stations. Caenocentrotus gibbosus (L. Agassiz and Desor) Plate 43, Fig. 20 Echinus (Toxopneustes) gibbosus L. Agassiz and Desor, 1846, p. 367. Caenocentrotus gibbosus H. L. Clark, 1912, p. 348. Grant and Hertlein, 1938, p. 29, pi. 10, figs. 3, 4. Mortensen, 1943, p. 321, pi. 34, figs. 3, 4; pi. 63, figs. 7, 8, 11, 13,19. This is another South American urchin which has not followed the coast north of the equator but unlike the preceding species it has followed 266 ALLAN HANCOCK PACIFIC EXPEDITIONS VOL. 8 PLATE 47 Fifi. 27. Clypeaster ochrus H. L. Clark, aboral view, x%, p. 297 Fig. 28. Clypeaster rotundus (A. Agassiz), aboral view, x%, p. 296 PLATE 48 Fig. 29. Clypeaster speciosus (Verrill), aboral view, x%, p. 308 Fig. 30. Clypeaster elongatus, new species, aboral view, x%, p. 308 PLATE 49 Fig. 31. Clypeaster elongatus, new species, oral view, x%, p. 308 Fig. 32. Dendraster excentricus Eschscholtz, aboral view, x%, p. 310 PLATE 50 Fig. 33. Clypeaster elongatus, new species, lateral view, x%, p. 308 Fig. 34. Dendraster laei'is, new species, aboral view, x%, p. 312 Fig. 35. Dendraster laevis, new species, oral view, x% Fig. 36. Dendraster laevis, new species, aboral view, smooth surface, XO. D CLARK : ECHINI OF WARMER EASTERN PACIFIC PL. 47 PL. 48 ALLAN HANCOCK PACIFIC EXPEDITIONS VOL.8 XO. D CLARK : ECHINI OF WARMER EASTERN PACIFIC PL. 49 PL. 50 ALLAN HANCOCK PACIFIC EXPEDITIONS VOL. 8 NO. 5 CLARK: ECHINI OF WARMER EASTERN PACIFIC PL. 51 PL. 52 ALLAN HANCOCK PACIFIC EXPEDITIONS VOL. 8 >■->«• • vr^'ir/-,"/ ' ^^^^ .<.'^' ^^^ . V'' ,^^^:::-: 7sm f'iii ' ■ "i^A- ^3?ipvsr a4sym^i&^ NO. 5 CLARK : ECHINI OF WARMER EASTERN PACIFIC PL. 53 ''%. i PL. 54 ALLAN HANCOCK PACIFIC EXPEDITIONS VOL. 8 '•--'4. "'*" "**^^PFPiiiiai'"' NO. 5 CLARK : ECHINI OF WARMER EASTERN PACIFIC 275 PLATE 51 Fig. 37. Dendraster mexicanus, new species, aboral view, rough surface, xl, p. 313 Fig. 38. Dendraster mexicanus, new species, aboral view, smooth surface, xl Fig. 39. Dendraster mexicanus, new species, oral view, xl PLATE 52 Fig. 40. Dendraster rugosus, new species, aboral view, x%, p. 318 Fig. 41. Dendraster rugosus, new species, oral view, x% PLATE 53 Fig. 42. Encope grandis L. Agassiz, aboral view, x%, p. 325 Fig. 43. Encope perspective L. Agassiz, aboral view, xl, p. 326 PLATE 54 Fig. 44. Encope tj.'etmorei A. H. Clark, aboral view, x%, p. 326 Fig. 45. Encope lae;-. >->-''^^v^'^v^ ;-::^/^'>'V.l y;>--i\: ■', ■ 46 Sifs;--C-. r- PL. 56 ALLAN HANCOCK PACIFIC EXPEDITIONS VOL. 8 XO. 3 CLARK : ECHINI OF WARMER EASTERN PACIFIC PL. 57 PL. 58 ALLAN HANCOCK PACIFIC EXPEDITIONS VOL. 8 ff./.-^.'^vf*/5»'^j-. ^^ 'S' ?>-': Mr- NO. 5 CLARK: ECHINI OF WARMER EASTERN PACIFIC PL. 59 PL. 60 ALLAN HANCOCK PACIFIC EXPEDITIONS VOL.8 NO. 5 CLARK: ECHINI OF WARMER EASTERN PACIFIC PL. 61 59 ^^U PL. 62 ALLAN HANCOCK PACIFIC EXPEDITIONS VOL. 8 NO. 5 CLARK: ECHINI OF WARMER EASTERN PACIFIC 291 PLATE 59 Fig. 54. Encope ecuadorensis, new species, aboral view, xj4, p. 333 Fig. 55. Encope ecuadorensis, new species, oral view, x% PLATE 60 Fig. 56. Encope fragilis, new species, aboral view, x%, p. 335 Fig. 57. Encope fragilis , new species, oral view, x% PLATE 61 Fig. 58. Encope insularis, new species, aboral view, xJ/2, P- 336 Fig. 59. Encope insularis, new species, oral view, xj^ PLATE 62 Fig. 60. Mellita longifissa Michelin, aboral view, xl, p. 337 Fig. 61. Cassidulus pacificus A. Agassiz, aboral view, x3, p. 338 292 ALLAN HANCOCK PACIFIC EXPEDITIONS VOL. 8 test with 4 or 5 rather large ambulacral pores in each arc, and short, stout, pointed primaiy spines of an almost black color. These spines tend to point upward or definitely forward or backward and give the impression that the urchins live in crevices or fissures in or between rocks. They do not bore holes (as Echinostrephus does) but it is possible that they enlarge crevices into which they fit themselves to some extent. Nearly all speci- mens have the primary spines pointing more or less forward or backward, parallel to the longer axis of the test. The largest specimen is 45 mm long (not including spines), 39 mm wide and 29 mm high. If the spines are included the corresponding measurements are roughly 80 x 55 x 40 mm. The color of all the Velero specimens is uniformly very dark but not black as one is inclined to think at first sight. It is rather a very deep purple, as dark in the very young specimens as in the adults. Specimens of the following species (VanBrunti) are often nearly as dark but the purple tinge is more evident especially on the oral side. In the shape of the test, this species is clearly more elongated and higher than the Panamic, and the pore-pairs are definitely fewer, only 4 or 5, as against 6 to 8. Hence there is no serious difficulty in identifying oblonga as it exists in the Eastern Pacific. The trouble comes in the Western Pacific where the ubiquitous mnthaei occurs so abundantly that it is difficult to draw any definite line between some of its very dark forms and the similarly dark oblonga. I think it must be agreed that oblonga is a variety gradually differentiating into a quite distinct species and in the Eastern Pacific it has attained that distinction. Distribution. — The Velero has found oblonga common at Sulphur Bay, Clarion Island, and at Braithwaite Bay, Socorro Island. A fair-sized adult was taken along shore at Bindloe Island, in the northern Galapagos Islands. Along the western side of South Seymour Island, 7 very young but quite typical oblonga were collected and at Cartago Bay, Albemarle Island, an adult specimen was found. But not a single specimen has been secured at Cocos Island or along the Mexican or Costa Rican coast. The indications are that oblonga has come from the west and established itself firmly at Clarion Island. From there it has spread to its near neighbor Socorro, and from these two islands it is extending its range southward into the Galapagos Islands but is not yet common there and has appar- ently reached a southern limit at Albemarle Island. Type. — Unknown. Type locality. — Unknown. Depth. — Shore and vtry shallow water. Specimens examined. — 85 specimens from 12 stations. NO. 5 CLARK : ECHINI OF WARMER EASTERN PACIFIC 293 Echinometra VanBrunti A. Agassiz Plate 46, Fig. 25 Echinometra VanBrunti A. Agassiz, 1863, p. 21. Heliocidaris stenopora H. L. Clark, 1912, p. 351, pi. 95, figs. 18-22; pi. 104, figs. 1-3; pi. 110, figs. 4,5. Echinometra VanBrunti Mortensen, 1943a, p. 373, pi. 45, figs. 1-3. This is apparently the commonest littoral sea-urchin of the tropical Eastern Pacific. The Velero collection contains 658 specimens taken at 92 stations. They range in size from young ones, nearly or quite circular, 5 to 10 mm in diameter, to large adults with a long axis exceeding 70 mm. Normal large adults have the lesser diameter nine-tenths of the longer, and the height is very generally about one-half the length. But there is considerable diversity and individuals having the normally lesser axis nearly or quite equalling the longitudinal axis are not very rare. There seems to be no doubt that Heliocidaris stenopora H. L. Clark is based on a large Echinometra Van Brunti as A. H. Clark, Ziesenhenne and Mortensen have recently pointed out. In the Velero collection there are some specimens in which the ambitus is nearly circular but they are com- monly less than 40 mm in diameter and not one would be identified as stenopora, as the tuberculation of the test is not coarse enough and the primary spines are not sufficiently stout. Mortensen inclines to recognize a variety rupicola although it occurs in the same areas as typical VanBrunti but the hundreds of specimens in the Velero collection do not, in my opinion, warrant the recognition of such a form. It was hoped and rather expected that among the Echinometras in the present collection, there would be from the Galapagos and Socorro Islands, some specimens of E. insularis but not one t3Tical example has been found. Some specimens from Costa Rica have only 5 pore-pairs in the ambulacra at the ambitus but they have 6 pairs abactinally and the general appearance and spinulation is like that of VanBrunti from the same region. Unfor- tunately there is but a single young individual from Clarion Island, and only two lots from Socorro. This series includes one very large adult and 32 small ones and they are typical VanBrunti. There are 78 specimens from some 20 stations in the Galapagos but none of them represent insularis, which justifies the suspicion that that supposed species is not really valid. The color of VanBrunti is remarkably uniform although the shade shows no little diversity. The basic color may be designated as violet especially when seen from below. There is a tendency on the one hand 294 ALLAN HANCOCK PACIFIC EXPEDITIONS VOL. 8 towards gray and on the other towards black. As a rule specimens from any one locality are much alike in color though large specimens may be darker than small ones. There is never any white nor any hint of green, but suggestions of a red violet are sometimes evident, and very young speci- mens (under 15 mm h. d.) may have a very definite red orange or a dull yellow tint around the peristome. Distribution. — ^According to Mortensen, this sea-urchin occurs as far north as "off Central California," but the Velero has not found it north of the Mexican boundary. Indeed she has not taken it anywhere on the western side of Lower California, although she has found it at various points in the Gulf as far north as Guaymas and Angel de la Guardia Island. It is common on the Mexican and Costa Rican coasts and in Panamic waters. Further south it has been taken by the Velero at various points on the coasts of Colombia, Ecuador, and Peru as far south as the Lobos de Afuera Islands. At the Galapagos Islands, it is quite common, being taken at more than 20 stations though never in large numbers. Some typical specimens were secured at Cocos Island and one good series was collected at Braithwaite Bay on Socorro. A single young specimen was collected at Clarion Island, but the Echinometras of Clarion Island need further collecting and study. Type.— M.C.Z. no. 1851 (Cotype). Type locality, — Acapulco, Mexico. Depth. — Shore to 29 fms. Specimens examined. — 658 specimens from 92 stations. Order EXOGYCLpIDA Family Glypeastridae Glypeaster europacificus H. L. Clark Plate 46, Fig. 26 Glypeaster europacificus H. L. Clark, 1914, p. 27, pis. 129, 130, 131, 136, fig. 1. The 102 specimens of this fine Glypeaster taken by the Velero form a very complete series from the babies 16x15 mm to the full grown adults just exceeding 200 mm in length. The largest specimen is 202 mm long by 200 mm wide and 30 mm high ; the test margin is about 6 mm thick. In most specimens the width of the test is not so great proportionately, a normal adult is 184 by 174 mm with the height 27 mm. The young are nearly or quite circular and many individuals continue so throughout life. Some, however, elongate appreciably; the longest of the present series have the width nine-tenths of the length. As a rule the height is about 15 NO. 5 CLARK : ECHINI OF WARMER EASTERN PACIFIC 295 per cent of the length but occasionally it is appreciably more, in extreme cases it may be 30 per cent. The general texture of the test is not very stout and hence injuries to the margin are rather frequent resulting in more or less conspicuous deformities. One specimen about 113 mm in length, with the width somewhat less, has the central portion of the petaloid area abruptly raised and flattened, resulting in a curious hat- shaped form as seen from the side. Color undergoes very considerable change with the growth. The youngest specimens are pale red violet, almost pink, above and cream color or nearly white below. With increasing size the color deepens. The upper surface becomes a deeper and more purple pink, violet, deep violet, brown violet, brown either j'ellowish or violet tinted, until in old speci- mens the very dark brown of the adult is reached. The ambulacral areas are often of a different shade so that the petals stand out more or less clearly. The cream-colored lower surface of the very young, becomes brownish yellow, yellow brown and ultimately a deep brown. In very old specimens there is a tendency for the ambulacral areas to darken and they may become more or less black at least along the midline. The dark shades of dried adults show considerable diversity, some specimens being quite gray. Young specimens, 25 mm or so in diameter may become deep violet above quite early, but occasionally remain light pink until sometime after that size is reached. Distribution. — The original material on which the species was based came from the Gulf of California, Clarion Island, Hood Island in the Galapagos, and Panama. The Velero has extended that range very little, except to the south; the present collection contains a nice set of 12 small specimens, 25-70 mm long, from off La Plata Island, Ecuador, in 45-55 fms. In the Galapagos area only once was europacificus met with — a single specimen in Academy Bay, Indefatigable Island in 10-25 fms. It was not found at Clarion or Socorro Islands. From Panama, Costa Rica and Mexico a number of specimens were secured but the bulk of the material, more than 60 specimens, was taken in the Gulf of California, at various points up to Angel de la Guardia Island. The bathymetric range of this Clypeaster seems to be from 10 to 95 fms. Tj;/.^.— U.S.N.M. No. 34226. Type locality.— Ezy of Panama, 7° 57' N, 78° 55' W, 33 fms. Depth.— \0-95 fms. Specimens examined. — 102 specimens from 24 stations. (Very likely this species is identical with Pfeffer's Alexandria magni- fica. Th. Mortensen) 296 ALLAN HANCOCK PACIFIC EXPEDITIONS VOL. 8 Clypeaster rotundus (A. Agassiz) Plate 47, Fig. 28 Stolonoclypus rotundus A. Agassiz, 1863, p. 25. Clypeaster rotundus A. Agassiz, 1872a, p, 100. H. L. Clark, 1914, p. 38, pis. 132, 133. Although adult specimens of this Clypeaster are easily distinguished from the preceding, the young, before reaching a length of 25 mm are very difficult to determine. They are nearly or quite circular, or a little longer than wide, and very flat. The lower surface, at first nearly white becomes yellowish, and as a rule is soon yellowish-brown, as in europacificus. The subsequent color changes are similar in the two species but the body form is usually characteristic, for europacificus has the interradial margins more or less evidently concave or at least straight, resulting in a pentagonal form with the length only a little, if at all, greater than the breadth. In rotundus the interradial margins are more or less convex, and the outline may be nearly circular, but as a rule the length is somewhat greater than the width. The largest specimen in the present collection is 175 mm by 160 ; the height is 27 mm, but a second specimen with the same length and breadth is only 20 mm high. The most nearly circular adult at hand is 146 mm long by 137 mm wide, but a specimen 37 mm long is 36 mm wide. Distribution. — There are 96 specimens in the Velero collection from 35 stations, well scattered along the coast from Santa Elena Bay, Ecuador to Georgia Island at the upper end of the Gulf of California. There are no records from the western coast of Lower California nor from anywhere above the Mexican boundary. There are 9 specimens from Clarion Island but none from Socorro, From Cocos Island there are two small specimens, dredged in relatively deep water, 30-50 fms. There are 20 specimens from 9 stations in the Galapagos Islands, but chiefly from Tagus Cove, Albe- marle Island. Some were taken in shallow water along shore but they were mostly dredged in 8-50 fms. Type.— M.C.Z. no. 2188. Type locality. — Acapulco, Mexico. Depth. — Shore to 50 fms. Specimens examined. — 96 specimens from 35 stations. NO. 5 CLARK: ECHINI OF WARMER EASTERN PACIFIC 297 Clypeaster ochrus H. L. Clark Plate 47, Fig. 27 Clypeaster ochrus H. L. Clark, 1914, p. 30, pi. 141, figs. 1-3. There can be no doubt of the close relationship between this species and speciosus but after a prolonged studj^ of all the Velero Clypeasters, it seems best to maintain ochrus as at least an incipient species. Typical speci- mens in good condition are easily recognized, but immature or badly pre- served individuals cause trouble. Moreover well-preserved specimens of the two species may be so much alike in color that it is very hard to deter- mine to which species they belong but the greater height of the test with its somewhat greater concavity can usually be relied upon to distinguish ochrus; in speciosus, the height is about one-fifth of the length, in ochrus it is one-fourth. In the Felero collection, there are 47 Clypeasters which may be referred to ochrus. They range from 5 to 114 mm in length but the most typical is 104x96 mm with a height of 28 mm, the mouth is sunken 12 mm below the test margin. The characteristic color is a yellow brown with the petaloid areas and the lower surface dark brown in rather marked contrast, but most of the specimens from Cocos (Nuez) Island, Costa Rica, Panama and Ecuador are chocolate brown or purple brown of a more or less deep shade, rarely, however, as deep as in speciosus. One young specimen (48 x 44 mm) from James Island, Galapagos, in 10 fms is red purple, rather dull above but quite bright orally. The smallest speci- men (5 mm), also from James Island, is a uniform light brown while the next largest (8 mm), from Ecuador, has the upper surface red violet. Distribution. — The most typical specimens are from Ecuador, Colombia and the Secas Islands, Panama, but very good specimens are from Albemarle Island in the Galapagos. A large number of Clypeasters dredged at Nuez Island, ofT Cocos Island, in 31-50 fms are best referred to this species although the only adult from this locality is very dark colored. It has, however, the proportions and general appearance of ochrus. No specimens of ochrus were taken north of Costa Rica. Records from other authors extend the known distribution as far north as La Paz, Lower California. Type.— M.C.Z. no. 4740. Type locality. — Acapulco, Mexico. Depth. — Shore to 50 fms. Specimens examined. — 47 specimens from 15 stations. 298 ALLAN HANCOCK PACIFIC EXPEDITIONS VOL. 8 PLATE 63 Fig. 62. Agassizia scrobiculata Valenciennes, aboral view, x%, p. 339 Fig. 63. Agassizia scrobiculata Valenciennes, lateral view, xYz PLATE 64 Fig. 64. Brisaster toivnsendi (A. Agassiz), aboral view, x%, p. 340 Fig. 65. Moira clotho (Michelin), aboral view, x%, p. 341 PLATE 65 Fig. 66. Brissopsis pacifica (A. Agassiz), aboral view, x^, p. 341 Fig. 67. Brissopsis pacifica (A. Agassiz), oral view, x% PLATE 66 Fig. 68. Plagiobrissus pacificus H. L. Clark, aboral view, xl, p. 342 Fig. 69. Plagiobrissus pacificus H. L. Clark, oral view, xl Fig. 70. Plagiobrissus pacificus H. L. Clark, lateral view, xl XO. D CLARK: ECHINI OF WARMER EASTERN PACIFIC PL. 63 PL. 64 ALLAN HANCOCK PACIFIC EXPEDITIONS VOL.8 XO. 3 CLARK : ECHINI OF WARMER EASTERN PACIFIC PL. 65 PL. 66 ALLAN HANCOCK PACIFIC EXPEDITIONS VOL.8 NO. 5 CLARK : ECHINI OF WARMER EASTERN PACIFIC PL, 67 PL. 68 ALLAN HANCOCK PACIFIC EXPEDITIONS VOL. 8 xo. :> CLARK : ECHINI OF WARMER EASTERN PACIFIC PL. 69 78 PL. 70 ALLAN HANCOCK PACIFIC EXPEDITIONS VOL.8 ', ■:..•':''*'', iff 1^1. ;J;'•.■.'';■-^^ «-lS^Vif»; NO. 5 CLARK: ECHINI OF WARMER EASTERN PACIFIC 307 PLATE 67 Fig. 71. Ihiobryssus coelus H. L. Clark, aboral view, x%, p. 343 Fig. 72. Idiobryssus coelus H. L. Clark, oral view, x% Fig. 73. Idiobryssus coelus H. L. Clark, lateral view, x% Fig. 74. Brissus latecarinatus (Leske), aboral view, x%, p. 343 PLATE 68 Fig. 75. Brissus latecarinatus (Leske), aboral view with spines, xl, p. 343 Fig. 76. Meoma grandis Gray, aboral view, rough, xJ/2, p. 344 Fig. 77. Meoma grandis Gray, aboral view, smooth, tlYz PLATE 69 Fig. 78. Spatangus californicus H. L. Clark, aboral view, x%, p. 345 Fig. 79. Spatangus californicus H. L. Clark, oral view, xl PLATE 70 Fig. 80. Gonimaretia lae-pical specimen being 65 x 70 x 9 mm but there is a great deal of diversity in shape and stoutness. Among the Channel Islands and south to Corona del Mar, this sand-dollar is very common in shallow water, from low water mark down to at least 40 fms. South of the Mexican line there seems to be a tendency to a more elongate form and a variety elongatus was described in 1935 (H. L. Clark, p. 122). The present collection con- tains few specimens that can be referred to this variety and 8 of these are young bare tests (bleached), 7 from the vicinity of Cedros Island, Lower California and 1 from ofl San Nicolas Island, California. A fifth speci- men is very different in appearance from these tests for although it is also NO. 5 CLARK : ECHINI OF WARMER EASTERN PACIFIC 311 bare it is not at all bleached but is a fine shade of brown, with the dark brown lines of the posterior half of the test (one of the supposed characters of elongatus) very conspicuous. It is from Laguna Beach, California, and measures 62 x 63 x 9 mm. One other specimen, also bare and not bleached, measures 39 x 37 x 5 mm and is of the same color and texture as specimens of the same size of the species of Dendraster described below as laevis. The petaloid area shows clearly that it is not laevis and hence it would seem to be an odd elongatus. Several other specimens show peculiarities that distinguish them as not normal. Two of these deserve a few words of description. The smaller, although not truly circular measures 43 x 43 mm. The anterior petal is long and narrow with a relatively uncrowded tuberculation, while the anterior paired petals are notably long and open at the tip. The color is a brown orange, particularly bright on the oral surface. It was taken north of Anacapa Island, California, in 15 fms. The other peculiar specimen measures 55 mm long by 61 mm in breadth. The anterior margin is nearly straight for about 15 mm while the posterior is straight for 20 mm or more. The apex of the test is about 30 mm from the anterior margin but the madreporite and the adjoining petal-bases are only 18 mm from the pos- terior margin. Associated with this, the lateral petals are unusually diverg- ing, the tips of the posterior pair being 22 mm apart. The anterior pair are also markedly diverging and very long, their tips 35 mm apart. The color of the test where bare is dull purple. The dense coat of spines is more or less orange or yellow but the color of the test is dominant on the upper surface; hence the general effect of the upper side is dark, dull brown orange; the lower side is predominantly brown orange. Coloration in excentricus is generally dull but shows a considerable diversity. The specimens from Oregon are essentially gray, the lighter with a tendency to cream color or dull white, especially orally, the darker ones to a dusky brown or even black. Most California specimens tend towards either a dull violet black or a bright maroon brown ; the latter in some cases might be called dark red. Owing to the dense coat of spines on the lower surface, the oral side is usually lighter or more brightly colored than the upper. As Dendrasters often congregate in great numbers on suitable bottoms, they tend to crowd each other into a more or less vertically inclined position and thus lie tier upon tier on a rough bottom over which the tidal currents flow back and forth. As a result of this the anterior fourth (more or less) of the animal becomes bleached to some degree while the not buried part remains dark. This peculiar bicoloration may be quite striking. 312 ALLAN HANCOCK PACIFIC EXPEDITIONS VOL.8 Distribution.— The Velero has taken excentricus at 42 stations, of which the northernmost was on the Oregon coast, 43° 41' N Lat. and the most southern near the tip of Lower California. No specimens have been taken at the Galapagos Islands or near any of the off shore islands. The great bulk of the material is from shallow water, out to about 20 fms, for the most part, but a few specimens have been taken in 40-50 fms and one specimen is labeled as from 113-127 fms, southeast of Marcial Point on the east coast of Lower California. There is perhaps some mistake about this label as no other specimens are known from the Gulf. Other authors extend the range to Alaska. Type. — Unknown. Type locality. — "An der Kuste der Insel Unalaschka, am Kamt- schatischen Meere." (Grant and Hertlein, 1938, p. 84) Depth. — Shore to 50 fms. Specimens examined. — ^Approximately 12,316 specimens from 42 stations. Dendraster laevis", new species Plate 50, Figs. 34-36 Length 52 mm, breadth 57 mm, height 6 mm; the breadth is thus markedly greater than the length; in young specimens, however, the length may be greater, a specimen 30 mm long is only 28 mm wide ; the largest specimen is 68 mm long, 75 mm wide and 8 mm high. Lower surface perfectly flat, the mouth not depressed at all. Both mouth and periproct are remarkably small, the former 2 mm, the latter scarcely 1 mm across. The petaloid area is remarkably small, only about 26 mm long by 29 mm across; the apex is 30 mm from the anterior margin. Anterior petal is longest but the anterior paired petals are nearly as long, 15 to 15.5 mm ; posterior petals about 1 1 mm. All the petals are about 6 mm wide. The pore-pairs are so small and the tuberculation of the whole test is so fine, there are no very evident distinctive features, but the pore-pairs make a single narrow band along each side of each petal ; the intermediate area is quite uniformly covered with minute tubercles. The four genital pores are quite evident but the ocular pores are indistinct. Both above and below the outlines of the plates composing the test are clearly shown and the pattern they make is striking. This feature is not at all evident in either the larger specimens or in the bare tests but it is a very handsome feature of the holotype. Primary spines short and slender, knobbed at the tip. ^ laevis — smooth, in reference to the remarkably close coat of delicate spines. NO. 5 CLARK : ECHINI OF WARMER EASTERN PACIFIC 313 lying flat and close so that the surface of the test is relatively smooth, quite unlike the condition in the other species of the genus. Pedicellariae very small and not abundant or peculiar. At each mouth angle is a group of 8-10 slender, acute primary spines, lying almost horizontally over the mouth. Color old gold orally, more nearly deep colonial buff aborally. In the largest specimens the color is very dull, especially on the upper side; orally the yellow-brown shade is very evident. This very distinct species was taken by the Velero at 9 stations between San Miguel Island, California, and the Coronados Islands, Mexico, in 4-30 fms. While most of the 118 specimens are young or very young, large adults were taken at 5 stations. The young are commonly quite yellow but the big adults are rather dull colored. A bare test when carefully cleaned revealed well the extraordinarily small petaloid area. The very small size of mouth and anus is another striking feature. Type. — Holotype, AHF no. 48, 82 paratypes. Type locality. — Station 976-39, north of Santa Barbara Island, Cali- fornia, 15-20 fms, May 28, 1939. Distribution. — Channel Islands, California to Coronados Islands, Mexico. Depth. — 4-30 fms. Specimens examined. — The type, paratypes and 35 specimens, from 9 stations. Dendraster mexicanus*, new species Plate 51, Figs. 37-39 Length 60 mm, breadth 60 mm, height 9 mm. Lower surface nearly flat, the mouth a little sunken. Test rather evenly elevated from margin to apex which is about 28 mm from posterior margin. Madreporite just pos- terior to apex. Petaloid area 32 by 33 mm with the anterior petal 18 mm and each of the anterior laterals about the same. Tuberculation of test very close and fine near margin but distinctly coarser on the elevated part of test, particularly within the petals; on oral surface the tuberculation is coarser and more widely spaced. Posterior petals about 15 mm long and 8 mm wide; they are slightly curved and diverge markedly, the inner margins being 15 mm apart at tips; poriferous areas very wide (about 3 mm), the ridges between the pore-pairs are very narrow but carry a crowded series of 3-9 minute tubercles. Areas between the poriferous zones carry fairly numerous, but not crowded tubercles of diverse sizes; 8 mexicanus, in reference to the southern habitat of the species. 314 ALLAN HANCOCK PACIFIC EXPEDITIONS VOL.8 PLATE 71 Fig. 82. Lovenia cordiformis A. Agassiz, aboral view, rough, x%, p. 347 Fig. 83. Lovenia cordiformis A. Agassiz, aboral view, smooth, x2 NO. 5 CLARK: ECHINI OF WARMER EASTERN PACIFIC PL. 71 NO. 5 CLARK : ECHINI OF WARMER EASTERN PACIFIC 317 none are conspicuously large but many are larger than the tubercles of the interradi'al areas. Anterior lateral petals similar in general tuberculation but the great breadth of the poriferous zones is very striking; the petals are 9 mm wide and the interporiferous area is only 3 mm. There are 8-10 (or even more) tubercles in each series across the poriferous area. Anterior unpaired petal is similar to the other petals but is perhaps a trifle narrower. Abactinal surface densely covered with spines of which those covering the interporiferous part of each of the paired petals are 2 or 3 mm long. This series of long spines forks at the distal end of the petal and continues to the test margin. Between petals 1 and 2 (as well as between 4 and 5 and 1 and 5) there are 2 parallel series of long spines running to the disk margin, where all spines are 3 or even 4 mm long. This belt of long spines forms the outer margin of the disk. Orally, the primary spines are 3-5 mm long, cinnamon buff to light purple drab in color and contrast decidedly with the dark purple drab of the disk. Pedicellariae very numerous, chiefly minute ophicephalous^ or triphyllous, crowded among the spines. Color of bare test dark purple drab; of the spine coat, light brownish drab. There are 7 adult specimens of this Dendraster, of which 2 are more or less cinnamon brown while the other 5 are of varying shades of purple drab. The latter, including the holotj'pe, are from San Rosario Bay, west coast of Lower California, in 15 fms. The other 2 and 13 very young individuals, 11-16 mm across, are from Lagoon Head Anchorage, west coast of Lower California, in 7 fms. The rough appearance of the posterior part of the dorsal surface, due to the long spines in radiating series (much as in rugosus) is a notable feature of this species but is not as important as the character and appearance of the petals on the cleaned test. Type. — Holotype, AHF no. 49, 4 paratypes. Type locality. — Station 610-37, Rosario Bay, Lower California, 15 fms, Februar}^ 28, 1937. Distribution. — West coast of Lower California from Rosario Bay to Lagoon Head Anchorage. Depth. — 7-15 fms. Specimens exmnined. — The type, paratypes and 15 specimens from 2 stations. 9 It is regrettable that Clark gives no information about these ophicephalous pedicellariae otherwise found only in Echinodiscus and (young) Astriclypcus among Scutellids. It would have been particularly interesting to learn whether they are bivalved as the other pedicellariae, bivalved ophicephalous pedicellariae being otherwise a very great rarity. In a couple of specimens of this species, a young one and a fine adult specimen, sent me by Prof. McCulloch, I do not find a single ophicephalous pedicellaria. 318 ALLAN HANCOCK PACIFIC EXPEDITIONS VOL.8 Dendraster rugosus^^, new species Plate 52, Figs. 40-41 Length 49 mm, breadth 47 mm, height 9 mm; the breadth is thus ver>' nearly equal to the length and it is probable that in fully grown indi- viduals the equality is complete. Lower surface almost completely flat, the oral area being very slightly depressed (when the animal is upside down). Test rather evenly elevated from margin to apex, which is definitely posterior in position, less than 20 mm from posterior margin. Petaloid area 26 by 30 mm with the anterior petal the longest and narrowest. Tuberculation of test very close and fine abactinally but with numerous primary tubercles scattered irregularly about, mostly in the petals or near the test margin; tuberculation of oral surface rather sparse except near margin. Posterior petals about 11 mm long and 5.5 mm wide; they are quite straight and diverge markedly, the inner margins being 12 mm apart at tips ; poriferous areas very narrow, about a millimeter wide, and the ridges between pore-pairs are so narrow they carry no primary tubercles. The areas between the poriferous zones carry longitudinal series of rela- tively large tubercles, about 4 basally but only 2 or 1 near the tips ; these series are more or less irregular and incomplete but give a definite char- acter to the petals. Anterior lateral petals essentially similar but larger, 14 by 6.5 mm; the poriferous zones are wider than in the posterior pair but are still quite narrow. The anterior unpaired petal is about 16 mm long but only 5 mm wide, for the poriferous zones are only a little curved and are as narrow as possible. Interporiferous areas in all 3 anterior petals show their primary tubercles rather conspicuously in 4 somewhat imperfect but still evident longitudinal series. Whole abactinal surface closely cov- ered with spines; the primary spines, borne by the large tubercles of the petals and by similar tubercles scattered over the interambulacral areas, are about 2 mm long, nearly white and rather sharp, the other spines are scarcely half as long and are thickened at the tip and rather bluntly pointed. Genital pores 4, fairly large ; the 5 ocular pores much less distinct. Mouth small, largely concealed by the long (4 or 5 mm) white spines crowding around it. Anterior primary spines of oral surface, 2 or 3 mm long, curve outwards to left and right on the anterior fifth of the test. Pedicellariae very small and hard to detect, not distinctive. Color of bare test pale ecru drab or pale vinaceous drab, spines whitish. "^^ rugosus — rough, in reference to the appearance caused by the numerous projecting primary spines. NO. 5 CLARK : ECHINI OF WARMER EASTERN PACIFIC 319 There are 4 specimens of this interesting Dendraster in the Velero col- lection. The holotype is the largest, with the others 37-39 mm long; the smallest 36 mm wide. They resemble the type in color and in ever}' other respect. They were taken in Bay San Sebastian, Vizcaino, west coast of Lower California, in 17 fms on a sandy bottom. The delicate coloration, the long white primary spines and the very narrow poriferous zones are quite distinctive. Type. — Holotype, AHF no. 50, 3 paratypes. Type locality. — Bay San Sebastian Vizcaino, Lower California, 17 fms, August 28, 1932. Distribution. — Bay San Sebastian Vizcaino, Lower California. Depth. — 17 fms. Specimens examined. — The tj^pe and paratypes from 1 station. Genus ENCOPE L. Agassiz In establishing the genus Encope L. Agassiz (1840, Cat. syst. ectyp. Echinod. Mus. Neocom. p. 6; 17) mentions only the species grandis. This species accordingly is the genotype. To take a species not originally in- cluded in the genus as the genotype is against the rules and against common sense. In a letter to me of May 8th, 1947 (the last but one he wrote to me) Clark writes: "A young palaeontologist here (viz. Dr. Durham) who is working on a Monograph of fossil Encopes insists that grandis is the type. As you of course know, I consider that emarginata is the type. If you agree with him that grandis is the type, I'll have to make some changes in my MS ; but if you agree with me that emarginata is the type then I shall be comfortably settled. At any rate grandis and emarginata are not congeneric, so one of them must have a new name." It is clear that Clark thus leaves to me the decision of the question which species is the genotype of Encope — and there cannot be the slightest doubt but that grandis is the genotype. Further, I thoroughly disagree with Clark in seeing two diiiferent generic tv^pes in grandis and emarginata. The only noteworthy difference is that the edge of the test is thicker in grandis than in the other species; but whether the edge is some 5 mm or only 2-3 mm thick is certainly not a difference of generic value, and any difference of morphological value does not exist between grandis and the other species. Particularly it must be emphasized that the internal struc- ture is exactly alike in both. As said in the preface I think Clark is here making too many species ; but without having access to the collections on which he is basing his 320 ALLAN HANCOCK PACIFIC EXPEDITIONS A Encope CaANDIS B E PERSPECTIVA VOL. 8 E E. MICROPORA F' F E COCOSI G E GALAPAGENSIS H E IRREGULARIS K E- IN SULAWS Text figure 1. Outline drawings at median longtitudinal axis of the species of Encope illustrated on Plates 53-59. NO. 5 CLARK: ECHINI OF WARMER EASTERN PACIFIC 321 A C GRANDIS o'E. PERSPECTIVA C t. WETMOREI D' E. LAE VIS K' E. INSULARIS Text figure 2. Outlines of transverse sections of same specinnens at areas of greatest thickness or height. 322 ALLAN HANCOCK PACIFIC EXPEDITIONS VOL. 8 various species I cannot go into a critical valuation of them, and I think it therefore the only fair thing to publish this part of his manuscript as he left it. Future investigations will have to decide about the value of all these species. One more species, Encope Stokesii L. Agassiz will have to be added to the AVest American species of Encope. Clark gradually became convinced that this species is only the young of micropore, but this is decidedly a mis- take. The internal structure of the test is markedly different from that t}'pical of Encope, the buccal cavity being not closed as it is in Encope but remaining in open connection with intestinal cavity. The subgenus Melli- tella established by Duncan (1889) for this species is therefore fully justified — perhaps it should rather form a genus of its own. It is verj' improbable that this species, so fairly common in the warmer region of West American seas, should not be represented in the Velero collections. Specimens of this species have probably been identified by Clark as Encope micropora. A re-examination of his material will be needed for settling this matter. Encope (Mellitella) Stokesii will be dealt with fully in the forthcom- ing Vol. IV.2 of my Monograph of the Echinoidea. Th. Mortensen The very large number (1,212) of Encopes taken by the Velero in her voyages to the tropical Pacific has necessitated a very detailed and time consuming comparative study of this well-defined and easily recognized genus. It was soon evident that more species of Encope are living on the western coast of tropical America than had been hitherto supposed and that the specific lines drawn needed realignment. In July, 1946, Austin Hobart Clark of the United States National Museum published a "Re- vision of the Pacific Species of the Genus Encope" with the description of a well-marked new species and the recognition of two new subspecies and a new variety. No statement as to the number of specimens available is made but Mr. Clark tells me that both the subspecies are based on "bare white tests devoid of spines." There are very few bare tests in the Velero col- lection and the identification of such tests is a difficult matter, with the possibility of error being very large, unless specimens with spines from the same locality^ accompany them. The hundreds of Encopes available from the Gulf of California show that the Encopes there are either the well- known form here listed as Encope grandis or micropore. It is fruitless to try and recognize either borealis or californica as subspecies or varieties, as they lack any constant association with any locality or any large group NO. 5 CLARK : ECHINI OF WARMER EASTERN PACIFIC 323 of specimens. On the other hand what Mr. Clark calls micropora galapa- gensis is a very well-marked species, not found elsewhere and apparently the only Encope found at the Galapagos Islands. If the tj'pe perspectiva jonesi really came from these islands, it is strange nothing like it occurs in the Velero collection. Its being a bare test debars it from further considera- tion in this report. The following key to the eleven species of Encope here recognized will require modification when more material from the Central and South American coast is available. A. Unpaired lunule in between the posterior petals for at least most of its length. B. Covering of test dorsally made up of rather slender spine- lets the tips of which are swollen but not flat-topped, nor inverted ; cones more or less considerably in contact . perspectiva BB. Covering of test dorsally made up of spinelets whose tips are more or less evidently inverted cones. Covering of test a fairly smooth pavement of cone-bases loosely in contact; color dark olive-gray . . . wetmorei Cone-bases larger and in close contact, making a very smooth pavement ; petals very large, straight, wide at tip ; color olive-brown or darker with marginal fringe of short brown or reddish-brown spinelets; lower surface brown laevis AA. Unpaired lunule not forward between posterior petals but more or less in line with the posterior lunules or anterior to them. C. Lunules usually more or less circular or oval and relatively small; test usually less than 120 mm in length, commonly about 90-100 mm. Spines of test very slender with only slightly enlarged tips . . micropora Test covered with the very numerous slender spines, each tipped with an oval ball, commonly white or light colored cocosi CC. Lunules much longer than wide; test often wider than long. 324 ALLAN HANCOCK PACIFIC EXPEDITIONS VOL. 8 D. Lunulas about twice as long as wide ; test thick and heavy, the margins a couple of millimeters or more in thickness. E. Test large, up to 150 mm h. d. ; unpaired lunule usually longer than posterior pair, , its anterior end a little in advance of the ' other two; test high, flattened between tip of anterior petal and the posterior lunule, highest point may be determinable as in middle or at either end ; normal color light brown above, with disk and lunule ^ margins purple .... galapagensis EE. Test smaller; unpaired lunule about the same size and about in line with posterior lunules. Color dark gray or blackish. Test flattened on top, commonly irregu- lar in outline, its greatest height about one-sixth or one-seventh of length; lun- ules relatively small and narrow, the pos- terior three nearly in line . . irregularis Test more curved on top, oval or broadly oval ; its height about one-tenth of length ; lunules long and narrow, the anterior trio slightly smaller .... ecuadorensis DD. Lunules 3 to 4 times as long as wide ; test thin and light with relatively thin edges. Unpaired lunule wider than other lunules; its anterior tip little or not at all in front of the posterior pair ...... fragilis Unpaired lunule long and narrow, its anterior end well in advance of the posterior pair . insularis In this key Clark, according to his views did not include the species grandis. It is easily distinguished from the rest of the species by its margin being thicker, some 5 mm or even more. Th. Mortensen NO. 5 CLARK: ECHINI OF WARMER EASTERN PACIFIC 325 Encope grandis L. Agassiz Plate 53, Fig. 42 Encope grandis L. Agassiz, 1841, p. 57, pi. 6. This easily recognized sea-urchin, or key-hole urchin, is very abundant in the Gulf of California and the Velero has brought home no fewer than 1,222 specimens, ranging in size from 40 x 40 mm to the big adults exceed- ing 100 mm in length with a breadth usually somewhat less but often somewhat greater. The largest specimen in the collection is 116 mm long by 111 mm wide and 16 mm thick, while another individual from the same station (689-37) is 111 mm long by 115 mm wide and 16 mm thick. The percentage of the total weight which the skeleton makes is very great but has not been worked out. Although the coarse and heavy build makes the specimens unmistakable, there is extraordinary diversity in the posterior unpaired lunule, which ranges from nearly circular to a long and narrow slit. The most striking case is a specimen 100 x 90 mm in which the lunule is circular and only 3 mm in diameter. This is such an extreme case it is probably pathological. At the other extreme is an indi- vidual with the lunule 20 mm long but only 6 mm wide. There is appar- ently no correlation between size or weight of the individual and the size of the lunule. Thus a specimen 100 x 105 mm has the lunule 17x10 mm but another specimen from the same lot, 92 x 92 mm has the lunule 33 x 16 mm. The color is dull purple, approaching black, or some shade of brown, ranging from fawn color in some young individuals to very deep blackish brown in adults. The margmal area is often darker than the center and the lower surface is lighter than the upper, often markedly so. But there is no distinctive feature in the coloration. Distribution. — The Velero took grandis at only 10 fathoms, all in the Gulf of California, mostly along shore, but occasionally it was dredged in