THE STOMACH OF THE CRAYFISH. 



53 



place, to the very remarkable and complicated apparatus 

 -which has already been spoken of, as a sort of gastric mill 



Fig. 9. — Astacus Jluviatilis.— A, the stomach with its outer coat removed, seen from the 

 left side ; B, the same viewed from the front, after removal of the anterior wall ; 

 C, the ossicles of the gastric mill separated from one another ; D, the prepy- 

 loric ossicle and median tooth, seen from the right side ; E, transverse section of 

 ' the pyloric region along the line xy in A (all x 2). c, cardiac ossicle ; cpv, cardio- 

 pyloric valve ; Vp, lateral pouch ; It, lateral tooth, seen through the wall of the 

 stomach in A; mg, mid-gut; int, median tooth, seen through the wall of the 

 stomach in A; ats, ossophagus; p, pyloric ossicle; pc, pterocardiac ossicle; 

 pp, prepyloric ossicle ; uc, uro-cardiac process ; t, convexities on the free surface 

 of its hinder end ; v l , median pyloric valve ; zc, zygocardiac ossicle. 



or food- crusher ; and, secondly, to a filter or strainer, 

 whereby the nutritive juices are separated from the in- 

 nutritious hard parts of the food and passed on into the 

 intestine. 



