Echinoderms 63 



indestructible by mere mutilation, for, 

 if torn limb from limb, each ray will 

 reproduce yet another ray. The larval 

 starfish is very unstarlike in farm, being 

 little more than a grotesque stomach 

 surrounded by hairs which slowly propel 

 it over the waves. In a very short time, 

 however, the upper and lower halves of 

 the star form about the stomach and the 

 creature sinks to the bottom ready to 

 face life. The so-called Cushion Stars 

 recall certain fossil forms that stand mid- 

 way between the starfishes and the 

 urchins, their rays being so short and 

 thick as to admit of little exploration 

 of rock crannies. 



In the Brittle Stars (Ophiuroidea), 

 which have a world- wide distribution, 

 the arms are sharply defined from the 

 central disc, and each limb is supported 

 by a series of plates that work one upon 

 the other like vertebrae, by means of very 

 powerful muscles. Whereas ordinary 



