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 
t. Cc 
°G PP Ketf/ int. 
mt LS Aaa = j 
Fic. 9.—Astacus fluviatilis.—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- 
lorie ossicle and median tooth, seen from the right side; E, transverse section of 
the pyloric region along the line zy in A (all x 2). ¢, cardiac ossicle ; epv, cardio- 
pylorie valve; Ip, lateral pouch ; lt, lateral tooth, seen through the wall of the 
stomach in A; mg, mid-gut; mt, median tooth, seen through the wall of the 
stomach in A; as, esophagus; p, pyloric ossicle; pe, pterocardiac ossicle ; 
pp, prepyloric ossicle; uc, uro-cardiac process ; f, convexities on the free surface 
of its hinder end ; v!, 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. 
