100 THE MALE FROG. 
ii. The bladder: a thin-walled bifid muscular sac, 
lying on the ventral surface of the large intestine 
and cloaca, its two lobes communicating freely 
with each other. It is invested by peritoneum 
and attached to the sides of the body by special 
peritoneal folds. 
Inflate the bladder with a blow pipe through the cloacal aperture: 
pass a seeker up the cloaca to determine the exact position of the 
opening from the bladder to the cloaca. Cut up the cloaca along 
one side: wash out its contents and examine the opening into the 
bladder. 
iii. The ureter or vas deferens behind the vesicula 
seminalis forms a very short tube opening into 
the dorsal wall of the cloaca almost exactly 
opposite the opening of the bladder on the ven- 
tral surface. The openings of the two ureters 
are close together on the apices of two small 
papille, overhung by a slight valvular projection 
of the mucous membrane of the cloaca. 
B. The Female Frog. 
1. The Reproductive organs. 
Dissect as in the male. 
i. The ovaries: a pair of black masses lying in folds 
of the peritoneum in front of the kidneys, in very 
much the same position as the testes in the male. 
Their shape and size vary much at different 
seasons of the year. On their surfaces are 
numerous rounded projections, like small shot ; 
these are ova in various stages of development : 
the smaller and younger ones are white; the 
larger and more mature ones black in one half, 
and white or yellowish in the other. 
ii. The oviducts: a pair of white much convoluted 
tubes with thick gelatinous walls. They com- 
mence with open mouths at the extreme front 
end of the body cavity, close to the outer side of 
the roots of the lungs; and run back increasing 
