R 

 Hblothuria 



md 



os 



anus ' 



C 



fldinoinetra 



'-/, 



anus 



" anus 

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



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

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

 ii first, i'o 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 poecum. [Combined from several sources.] 



