GULF OF MEXICO 



385 



2. Spicules large tables with disk developed as a cross; rarely arms of cross utiited so a complete disk is formed. Large, 

 thick-skinned forms with ventral side set off as a sole with marginal papillae 4. Bathyploles Oestergren, p. 386 



2. Spicules small to large tables; disk not cross-shaped 3 



3. Appendages large papillae and feet, all in distinct rows. Tables of varying size, often the large ones with spire reduced. 



5. Amphigymnaa Walsh, p. 387 



3. Appendages small, scattered or marginal 4 



4. Numerous tube feet, resembling short threads, distributed over most of the sack-like body -.2. Mesothuria Ludwig, p. 385 

 4. Few marginal feet, wart-like 3. Zygothuria Perrier, p. 386 



Genus 1 PSEUDOSTICHOPUS Th6el, 1882 



Of the seven incompletely kno\vn species re- 

 ported from the Atlantic Ocean, one is listed from 

 the Gulf of Mexico. For the others which very 

 likely may belong to the fauna, see Mortensen, 

 1927, p. 367, or Deichmann, 1930, p. 86. 



Pseudostichopus occultatus v. Marenzeller 



Pseudostichopus occullatus v. Marenzeller, 1893a, p. 15, 

 pi. 4, fig. 9; Deichmann, 1930, p. 89; 1940, p. 190. 



Diagnosis. — Small species, 4 to 6 cm., body 

 normally covered with Cresfis-shells, etc. Larger 

 tube feet along sides of body. A few perforated 

 plates usually found near anus; tentacles with 

 curved rods; gonads with delicate crosses. Type: 

 Possibly in Vienna. Type locality: Eastern Med- 

 iterranean. Distribution: Eastern Atlantic; 

 northwest of Cuba. From 160 to 1,100 fathoms. 

 The covering of Pteropod shells seems to be 

 characteristic of this small species. 



Genus 2 MESOTHURIA Ludwig, 1894 



KEY TO THE SPECIES REPORTED FROM THE GULF OF MEXICO 



1. Deposits triradiate tables 1. Mesothuria maroccana Perrier, p. 385 



1 . Deposits quadriradiate tables 2 



2. Feet of almost uniform size scattered over most of the upper and lower side 2. Mesothuria verrilli Th6el, p. 385 



2. Feet dorsaily small, absent on most of the ventrum 3 



3. Tables of moderate size with one circle of about eight holes, sometime a few accessory ones 



3. Mesothuria intestinalis (Ascanius and Rathke), p. 385 



3. Tables with enormous disks with numerous holes in several circles 4. Mesothuria gargantua Deichmann, p. 386 



1 Mesothuria maroccana Perrier 



Mesothuria maroccana Perrier, 1902, p. 312, pi. 16, 

 figs. 32-35; Deichmann, 1930, p. 97, pi. 7, figs. 2-7; 

 1940, p. 191. 



Diagonsis. — Small form, 4 to 8 cm. long, with 

 feet largest along the flanks, well-developed on the 

 dorsum and totally lacking on the ventrum. 

 Spicules, regular tables mostly with six holes; 

 margin smooth or undulating; spire composed of 

 three rods and ending in three diverging arms with 

 few teeth. Type: Paris. Type locality: Off 

 Morocco, 2,105 meters. Distribution: Eastern 

 Atlantic; also widespread in the West Indies; in 

 the Gulf of Mexico reported from San Nicholas 

 Chaanel, northern Cuba, 500 fathoms. From 

 500 to 1,350 fathoms. 



2 Mesothuria verrilli (Th^el) 



Holothuria verrilli (partim) Th6el, 1886b, p. 6. 

 Mesothuria verrilli Deichmann, 1930, p. 93, pi. 6, figs. 

 1-8; 1940, p. 192. 



Diagnosis. — Up to 30 cm. long. Feet small, 

 thread-like, more or less uniformly scattered, 



absent on anterior part of ventrum. Spicules 

 tables with regular to irregular disk with about 

 eight holes, sometimes reduced with age. Feet 

 with small tables, often with disk completely 

 resorbed. Type: Museum of Comparative 

 Zoology. Type locality: Ambergris Key, British 

 Hondiu-as. Distribution: Eastern and western 

 Atlantic, from 382 to 1,000 fathoms; in the West 

 Indies common along the Lesser Antilles and 

 recently secured by the Atlantis along the north 

 coast of Cuba. The species may be expected off the 

 shores of Yucatdn. 



3 Mesothuria intestinalis (Ascanius and Rathke) 



Holothuria intestinalis Ascanius and Rathke, 1805, 

 Fasc. 5, p. 5, pi. 45. 



Mesothuria intestinalis Deichmann, 1930, p. 94, pi. 6, 

 figs. 9-10. 



Diagnosis. — Elongate thin-skinned form with 

 almost naked ventrum, large lateral feet and 

 smaller dorsal ones. Spicules tables with eight 

 oval holes; feet with end plate and tables of same 

 size and shape as those in the skin. Type: Not 



