THE ALIMENTARY CANAL. 



83 



lower animals, the intestines lie more or less loose in the 

 abdomen ; but in the Crocodile, and likewise in Birds and 

 Mammals, they are supported by a membrane called mes- 

 entery. 



FIG. 4S. Anatomy of the Carp: 6r, branchiae, or gills; c, heart : /, liver; vn, vn', 

 swimming-bladder; </. intestinal canal ; o, ovarium ; , ureter; a, anus; o', gen- 

 ital opening; u', opening of ureter. The side-view shows the disposition ot" the 

 muscles in vertical flakes. 



