THE ECHINODERMS 



195 



Brittle stars. - - The arms of the brittle stars and basket 

 fish (Fig. 115) are noticeably different from those of the starfish. 

 They are slender, and exceedingly flexible, but easily broken off ; 

 hence the name brittle star. 



The food of the brittle stars consists of minute organisms 



FIG. 115. A basket star. (From v^iarh.) 



and decaying organic matter lying on the mud of the sea bot- 

 tom. It is scooped into the mouth by special tube feet. Loco- 

 motion is comparatively rapid. The arms are bent laterally, 

 and enable animals belonging to certain species to " run," or 

 climb, and probably to swim. 



