RANA. 343 
receives blood from the kidneys by vewa/s and from the 
genital organs. It then passes forwards through the liver, 
which it drains by paired Aepatics, and discharges itself 
into the sinus venosus. 
The two lungs have separate pulmonary veins which fall 
together into the left auricle of the heart. 
In the frog there are no paired cardinal veins* as in the 
skate, their function being executed by the unpaired post- 
caval. On the other hand, the presence of a renal-portal 
system is a feature of both types. 
Fig. 241.—VENTRAL VIEW OF THE FEMALE UROGENITAL 
ORGANS OF A Froc. = (dd nat.) 
Internal Opening of 
Oviduct. 
Oviduct. 
Corpus 
Adiposum. 
Ovary. 
Adrenal. 
“(Jterine” Portion 
of Oviduct. 
Aperture of Ureter. , 
Aperture of Oviduct. 
Ureter. 
Cloaca. 
The cloaca is slit open to show openings of ureters and oviducts. 
The &zdneys are long, red bodies lying in the dorsal 
wall of the abdominal cavity. Each has a thin, yellow, 
adrenal body on its ventral face. <A ureter 
Urogenital. eaves the outer posterior border of each kidney 
to open separately into the cloaca just dorsal to the opening 
of the urinary bladder already noticed. 
In the male the estes are oval, light-yellow bodies lying 
ventral to the anterior part of thekidneys and attached to them 
by peritoneum. A number of fine tubules, the vasa effer- 
entia, pass from the testes into the kidney, through which they 
eventually communicate with the ureters. These, therefore, 
* They are present in the Urodela. 
