HOLOTHURIOIDEA 



373 



usually present also in the mid- ventral ambulacrum. Calcareous 

 deposits pointed rods or derivatives of such, not arranged longi- 

 tudinally in the dorsal papillae. Calcareous ring incompletely 

 developed. Gonads of various forms, simple tubes or large 

 branched organs. Mesentery a continuous membrane, well 

 developed also on the second intestinal loop. 

 Three genera known from the N.E. Atlantic. 



Key to the N.E. Atlantic genera of Psychropotidce. 



1. A large dorsal appendage present ..... 2 

 No ,, ,, ,, ,, . . Benthodytes Theel 



2. Appendage short, situated anteriorly on posterior third of body 



Euphronides Theel 

 Appendage very long, situated on the posterior end of body 



Psychropotes Theel 



Benthodytes Theel. (Fig. 221.) 



Body more or less depressed. Mouth ventral. Anus dorsal. 

 Tentacles 12 (?)-20. Tube-feet in a double row in the mid-ventral 

 radius ; laterally the feet are 

 united into a web. Dorsal 

 papilla? in variable numbers, 

 sometimes absent. No large 

 dorsal appendage. Deposits 

 few, often very large, cross - 

 shaped spinous rods with an 

 outer central projection, or 

 simple spinous rods. 



Four species of this genus are 

 known from the N.E. Atlantic, 

 namely, Benthodytes glutinosa 

 Perrier,^ from off the Azores 

 ("Talisman'"), south of the 

 Canaries, and 48° 29' N., 13° 55' 

 W. ("Michael Sars "), in depths 

 of 1400-3432 m. ; B. janthina 

 V. Marenz., from the Bay of 

 Biscay ("Michael Sars"), off the 

 W. coast of Morocco down to the 

 Cape Verdes, and from the Azores, in depths of 2252-4700 m. 

 (" Hirondelle ", " Princesse Alice ") ; B. lingua Perr., from south 



^ Herouard (" Monaco ", Ixvi., p. 102) thinks that this species is identical 

 with B. typica Theel ; the present author lias had no opportunity himself 

 of examining these forms, but is very much inclined to agree with Herouard 

 in this opinion. 



Fig. 221. — Benthodytes typica ; 

 ventral side. Nat. size. 

 (After Theel, ''Challenger'' Holoth., i.) 



