ECHINODERMATA. 



29 



OKDER II. ASTEEOIDEA (Star-fishes). 



Fam. a. Asteracanthiidse. Uraster (Asteracanthicni), 



Heliaster. 



Fam. &. Solasteridse. Rolaster, Crilella (Echinaster). 

 Fam. c. Linckiad&e. Linckia. 

 Fam. d. Asterinidae. Asterina, Palmipes, Gfoniaster, 



Culcita. 

 Fam. e. Astropectinidae. Astropecten (Asterias), Cteno- 



discus, Luidia, Archaster. 

 Fam. f. Pterasteridse. Pteraster, Hymenaster. 

 Fam. g. Brisingidae. Brisinga. 

 Fam. h. *Palaeasterida3. Palceaster. 



Fig. 25. Asteroidea. Archaster bifrons, viewed from the dorsal aspect. Three-fourths 

 of the natural size. (After Sir Wyville Thomson.) 



