FISHES. 
495 
bottom of the water, and Mr. Gosse says there is some reason for 
c °nsidering it to be the first rudimentary form of the air-breathing 
lung. 
°r ascend or descend in the bosom of the waters ; it is, moreover, 
remarked that it is very small in those species which swim at the 
Fig, 341. Anatomy ol' the Carp. 
,)r . the bronchia*, or gill openings ; the heart ; f, the liver ; vn. swimming bladders ; ci, intestinal canal ; 
o, the ovarium; u, 'urethra; a, anus; o', oviduct. 
