HOLOTHURIOIDEA 



38' 



Alice ") ; Ps. lapidus Her., off the Azores, 4020 m. (" Princesse 

 Alice " ; only one specimen known) ; Ps. Marenzelleri Her., 

 36° 54' N., 20° 46' W., 4400 m. (" Princess Alice ") ; Ps. occul- 



1 2 3 



Fig. 230. — Pseudostichopus depressus ; dorsal (1) and ventral side (2) and 

 side view (3). The small depression in the anterior third of body seen 

 in (1) and (3) is the madreporite. Somewhat reduced. (After 

 Herouard, " Monaco ", xxi.) 



tahis Marenzeller, off N.W. Spain, ca. 500 m. (" Hirondelle "). 

 also found in the Mediterranean, in depths of 415-1445 m. ; Ps. 

 viUosus Theel, 37° 16' N., 20° 11' W., 4275 m. (" Princesse Alice ")* 

 otherwise of cosmopolitan distribution, ca. 2600-5300 m. 



Key to the N.E. Atlatitic species of Pseudostichopus.'^ 



1. No foreign particles adhering to the skin. Large, round, solid 



deposits with warty or spinous surface present in the skin 

 of ventral side (" Talisman " Holoth., p. 333, PI. XVII. 



15-20) Ps. atlanticus Perr. 



Body covered by foreign particles ; deposits, if present, not large, 

 solid bodies •••••... 2 



2. A broad, thick marginal brim in anterior half of body ; madre- 



porite large, externally visible as an oval impression on the 

 dorsal side. No calcareous deposits {''Monaco'", xxi., p. 15, 

 PI. II. 15-18) ..... Ps. depressus ^^v. 



No thick marginal brim, or, at most, an indication of one; 

 madreporite not large and visible externally ... 3 



1 This key has in the main been worked out by Miss Deichmann. 



