366 



ECHINODERMS OF THE BRITISH ISLES 



3 anterior, 1 posterior pair of dorsal pai^illie, not united by a 

 web ....... ELpidia Theel 



Calcareous rods simple (Fig. 217, 5), without long median pro- 

 cesses ......... 4 



4. C -shaped bodies present .... Ellipinion Her. 



„ „ absent ....... 5 



5. Three pairs of dorsal papillae at anterior end of body, united or 



not by a web ; 7-9 tube -feet on each side of body 



Kolga Dan. and Kor. 

 Five pairs of dorsal papillae at anterior end of body, not united 

 by a web ; 12 tube-feet on each side of body 



Irpa Dan. and Kor. 

 G. Dorsal papillae united by a web, at least at their base, forming 

 a fan-like prominence above the anterior end of the body ; 

 lateral tube -feet large, not united by a web . Peniagone Theel 

 Dorsal papillae forming an anterior prolongation of the body, not 

 raised above the usually fiat dorsal surface ; lateral tube -feet 

 confined to the posterior end of body, united so as to form a 

 fringe round the posterior end . . Scotoanassa Theel 



Elpidia Theel. (Fig. 218, 1.) 



Body ovoid ; the skin fairly stiff from the numerous calcareous 

 deposits. Mouth ventral, 10 tentacles. Tube-feet of lateral 

 ambulacra few, equally distributed along the whole edge of 

 body. Dorsal papillae 3 anterior and 1 posterior pairs, not united 



Fig. 218. — Outline figures of Elpidia glacialis, dorsal side (1) ; Scotoanassa 

 translucida, dorsal side (2) and in side view (3); Ellipinion Delagei, 

 dorsal (4) and ventral side (5). The two first about half size, the last 

 natural size. (After Theel, Elpidia, and Herouard, '^Monaco'", xxi.) 



by a web. Wheels present, but few in numbers. The calcar- 

 eous rods pointed, usually with some long median processes 

 (Fig. 217, 4). 



Only one species known wdth certainty of the genus as thus 

 restricted, namely Elpidia glacialis Theel (Fig. 218, 1), which was 



