THE APODOUS HOLOTHURIANS 179 



REMARKS. Although Sluiter had only a single specimen, he made such good 

 use of that one that we have a very satisfactory knowledge of the morphology of 

 this noteworthy holothurian. 



EUPYRGUS Lutken, 1857. 



Echinosoma Semper, 1868. 



Tentacles 15, simple and without digits or ampullae. Body tapering poste- 

 riorly into a short but distinct caudal appendage. Radial pieces of calcareous 

 ring with no posterior prolongations, or with very slight ones on those of the 

 ventral side. Longitudinal muscles simple and unpaired. Calcareous deposits 

 in the form of tables with perforated disc and high spire. Phosphatic deposits 

 wanting. 



This interesting genus of very small holothurians was long monotypic, but 

 Ostergren ( :05fo) has recently added a second species. Although the tentacles 

 lack digits, Eupyrgus has little in common with Aphelodactyla and its relation- 

 ships are quite obscure. It is even a debatable question whether it has not 

 sprung from a different ancestry than that of the other Molpadiidse. The type 

 species is a distinctly Arctic animal, but the recently discovered one is found 

 farther to the south. Verrill's ('85&) Echinosoma abyssicola, recorded from 

 off the New England coast in 3,718 m., is a simple nomen nudum, and is very 

 possibly an Echinocucumis or perhaps a Sphaerothuria. 



KEY TO THE SPECIKS OF EUPYRGUS. 



Some or all of the calcareous tables stout, with disc 190-300 p in diameter, perforated with 

 20-30 (often fewer, rarely more) holes SCABER 



Tables more slender, with base 125-250 p, perforated with 40-60 (rarely fewer, often more) 

 holes PACIFICUS 



ETJPYKGTJS SCABER. 

 PLATE XTI, FIGS. 16-27. 



Eupyrgus scaber Lutken, 1857, p. 22. 

 Echinosoma hispidum Semper, 1868, p. 44. 



LENGTH. 9-12 mm., with a diameter of about 5. 



COLOR. Grayish. 



DISTRIBUTION. Reported from between Port Hood, Cape Breton and eastern 

 point of Prince Edward Island, and off Bonaventure Island (Whiteaves) ; Sal- 

 mon Bay, Caribou Island and Long Island, Cateau Bay (Packard) ; southern 

 Labrador (Verrill) ; Greenland (Lutken, et al.) ; Spitzbergen (Ljungman, Theel, 

 et al.) ; Barents Sea (D'Urban et al.) ; Kara Sea (Stuxberg); Finmark (Nor- 

 man); and coast of Alaska (Clark, antea) ; in depths of 7-480 m. ; also from 

 Indian Ocean (Walsh). 



REMARKS. Although long known, this species has been little studied and no 

 good figures of the animal or its deposits were published until recently (Norman 



