38G ECHINODERMS OF THE BRITISH ISLES 



[Paroriza H^rouard.] 



Body cylindrical, only slightly flattened on the ventral side, 

 which does not form a ventral sole and is not separated from the 

 dorsal side by a marginal fringe. Mouth ventral ; anus sometimes 

 in a more or less distinct longitudinal furrow. Twenty tentacles. 

 Tube -feet well developed, but not regularly arranged ; those of 

 the dorsal side slender papillae. Skin naked. No calcareous 

 deposits. Gonads on both sides of the dorsal mesentery. 



Two species known from the N.E. Atlantic, viz. Paroriza 

 Prouhoi Herouard, from the Bay of Biscay and off the Azores, 

 4360-4380 m. (" Princesse Alice"); and P. pallens (Koehler) 

 (S3ni. Stichopus pallens Koehler), from Bay of Biscay, 1300 m. 

 (" Caudan "). The two species are thus distinguished : 



Mid-ventral radius without tube-feet (" Monaco ", xxi., p. 24, 

 PI. VIII. 1 ; Ixvi., p. 29, PL II. 3-4) . P. Prouhoi Her. 



Mid-ventral radius with some scattered tube-feet {Echinod. 

 " Caudan'", p. Ill, Figs. 1, 45) . . P. pallens (Koehler) 



Both species are large forms, up to 22-23 cm. An Actinian, 

 Sicyopus commensalis Gravier, has been found attached to the 

 skin, above the mouth, in P. Prouhoi. 



[Pseudostichopus Theel.] (Fig. 230.) 



Body cylindrical or slightly flattened on the ventral side, which 

 does not form a ventral sole and is usually not separated from the 

 dorsal side by a marginal brim. Mouth subterminal ; tentacles 

 16-20. Tube-feet very small and numerous, often apparently 

 double or triple, usually concealed by the close coat of foreign 

 bodies — sponge spicules, Pteropod shells, Foraminifera, etc. — 

 which cover the whole skin. Retractor muscles developed in 

 the posterior end of the four paired ambulacra, not on the mid- 

 ventral. To these it is due that the posterior end is usually 

 contracted on preservation, forming a longitudinal furrow at the 

 ventral end of which the anus is situated. Calcareous deposits 

 rare or absent. Gonads on both sides of the dorsal mesentery. 



Deep-sea forms of moderate or rather small size. 



Seven species are known from the N.E. Atlantic, namely, 

 Pseudostichopus atlanticus R. Perrier, from 42° 19' N., 23° 36' W., 

 4060 m. ; Ps. dejwessus Herouard, 39° 54' N., 20° 17' W., 4360 m. 

 ("' Princesse Alice " ; only one specimen known) (Fig. 230) ; 

 Ps. globigerince Herouard, Bay of Biscay, 4380 m. ("' Princesse 



