ECHINODERMS 



159 



of closely branched, fluffy glands (Z), extending the entire 

 length of each arm and opening into the pyloric stomach. 



The starfishes are carnivorous and highly voracious, de- 

 vouring large numbers of barnacles and mollusks which hap- 

 pen in their path. If these are small and free they are 

 taken directly into the stomach, but when one of relatively 

 large size is encountered the starfish settles down upon it, 

 and, slowly pushing the cardiac stomach through the mouth, 

 envelops it in the folds. Digestive fluids are now poured 

 over it, and the victim is speedily despatched and in a partly 

 digested condition is gradually absorbed into the body, leav- 



f. 



ff 



FIG. 98. Dissection of starfish to show : a, pyloric stomach ; 5, bile-ducts (above), 

 cardiac stomach (below) ; b.c., body-cavity ; /, feet ; g, spines ; i, intestine ; 

 I, liver; m, mouth; m.p., madreporic plate; r, reservoir; r.c., ring canal; 

 r.m., stomach retractor muscle ; r.v., radial vessel ; , stone canal ; t, respira- 

 tory tree. 



ing the shell and other indigestible matters upon the exte- 

 rior. Oysters and clams close their shells when thus attacked, 

 but a steady, continuous pull on the part of the starfish 

 finally opens them, and the stomach is spread over the fleshy 

 portions with speedily fatal results. In the interior of the 

 body the food is transferred to the pyloric stomach, sub- 

 jected to the action of the liver, and when completely dis- 

 solved is borne to all parts of the body. 



