R 



Jfolothuricr 



B 



Jfntedon, Pentacrmus. 



anus 



s anus 

 FIG. 382. Diagram of the course of the alimentary canal in various Echinoderms. The 



body is viewed from the oral side, md, ms, Mesenteries ; as, food-grooves or ainbulacral furrows 

 of the tegmen calycis ; m, madreporite ; x, commencement of the backward coil of the intestine ; 

 ii first, i-2 second (backward) coil of the intestine ; s, siphon, accessory intestine ; 1 and 2 (in F) 

 the two points at which the accessory intestine enters the principal intestine ; sj, free portion of 

 the accessory intestine ; s 2 , portion of the same in contact with the principal intestine ; coec, in- 

 testinal ccecum. [Combined from several sources.] 



