ANATOMY OF BATRACHIANS. 469 
toads and frogs are so highly developed. The trachea is 
short. : 
The heart has two auricles, the right one the larger, and a 
single ventricle; but in Proteus the auricles connect with 
each other, and in the salamanders there is a hole in the par- 
tition separating the auricles. There are also indications of 
Fig. 481—Mouth and digestive 
canalof a Tadpole. A, mouth; 2, 
intestine coiled on itself ; ¢, liver ; 
d, hepatic duct; ¢, pancreas; /, 
rudimentary hind lege i g, rectum. 
—After Gervais and Van Beneden. 
a partition in the ventricle. Fig. 
432 represents the circulatory or- 
* Fig. 432.—Tadpole of a Frog. Tf 
gans of a tadpole, after the gills dont cava; 9, right muciole 3, pul- 
*o Mouary vein and its origin in the 
have become absorbed, and before ty "Wags: a iste suriees Bove 
j rer in tticle ; 6, arterial bulb ; 7, branchial 
the aortic arches are reduced in artery and its internal branches; 8, 
number. branchial veins ; 9, aorta; 10, pul- 
a monary artery and its subdivisions 
The nervous system is much inthe iungs.—After Gervais and Van. 
as in fishes; but the optic lobes ™™*4* 
are rather small; the cerebrum is small.* The kidneys are 
in many respects like those of fishes, especially sharks, as: 
is the internal reproductive system. The ovaries are greatly 
enlarged during the breeding season. The sperm is usually 
passed to the kidney, and thence through the ureters out of 
the cloaca. The oviducts and ureters have a common outlet 
* See Wyman, on the Nervous System of Rana pipiens. Smiths 
Contr. 1853. : 
