224 



ZOOLOGY. 



called (Fig. 187), there exists no longer any organ of locomo- 

 tion : the destiny of the animal is to live fixed to the soil, and 

 its mouth is surrounded with moveable tubercles (Fig. 189), 



Fig. 186. Holothuria ; Sea Cucumber. 



by means of which it gathers in the surrounding waters the 

 corpuscles necessary to its nutrition ; in general, a portion of 



Fig. 187. The Coral Polyp. 



Fig. 188. Ehizostoma; Medusa, 

 or Sea Jelly. 



the integuments becomes ossified, so as to form for it a kind 

 of calcareous or horny dwelling (Fig. 190); and in most cases 

 also the young spring from granulations arising on the surface 



