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. 
F!G. 48 .— Anatomy of the Carp: hr, branchiae, or gills; c, heart; /, liver; vn, vn\ 
swimming-bladder; ci, intestinal canal; o, ovarium ; u, ureter; a, anus; o', gen¬ 
ital opening; u\ opening of ureter. The side-view shows the disposition of the 
muscles in vertical flakes. 
