iv THE INTERNAL STRUCTURE 77 



body cavity near the base of the lung by a wide funnel- 

 shaped mouth into which the eggs find their way after they 

 have been discharged into the ccelom. The walls of the 

 oviducts are thick and glandular except toward the posterior 

 end, where they become expanded into thin, very disten- 

 sible sacs, the uteri, in which the eggs collect before being 

 laid. The uteri open separately into the dorsal side of the 

 cloaca. 



The gonads of the male, or testes, are very different in 

 size and appearance from the ovaries. Each testis is an 

 ovoid, whitish organ, occupying a similar position to the 

 ovary in the body cavity and suspended in a similar way by 

 a membrane, the mesorchium, to the dorsal body wall. At 

 the anterior end of both the ovaries and testes are attached 

 the fat bodies, corpora adiposa, which are easily recognizable 

 on account of their yellow color and their division into a 

 number of finger-like lobes. 



The kidneys are reddish, flattened, oblong organs lying 

 against the dorsal body wall on either side of the vertebral 

 column. Their position is somewhat behind the middle 

 of the body cavity, and they are brought into view when 

 the other abdominal viscera are removed or pushed aside. 

 Each kidney is connected with a tube, the ureter, which 

 runs along its outer edge and empties, near the opening of 

 its fellow, into the dorsal side of the cloaca. In the male 

 the ureters are expanded distally to form seminal vesicles, 

 which in some species of frogs reach a considerable size. 

 The urinary bladder is a large, bilobed sac lying in the pos- 

 terior end of the body cavity, and opening into the ventral 

 side of the cloaca just below the openings of the ureters. 

 If the bladder is inflated by means of a blow pipe inserted 

 into the cloaca, it will swell to a large size, and an accurate 

 idea may be gained of its form and connections. 



