207 
of the Oviviviparous Shark, &c. 
urinary bladder, which is of an oval shape, and partially 
divided into two by a septum, on each side of which the 
ureters enter it. From this cavity, the penis is continued like 
the neck of a Florence flask, and the semen, before it can 
arrive at the penis, fills the bladder, and is propelled by the 
action of the muscular coats of that cavity, by which means 
the semen acquires velocity, and the penis is rendered turgid 
during the whole time that such force is applied to the liquid 
passing through it. 
This bladder at other times is a reservoir for the urine, 
which must be considered a secondary office in a fish con- 
stantly living in water. 
The situation and appearance of the testicles are seen in the 
annexed drawing, which makes a description of them un- 
necessary. 
The female organs, before they undergo the necessary 
changes to form the eggs, and prepare them to receive the 
influence of the male, are very little developed ; the ovaria are 
not larger than the testicles of the male before the breeding 
season, and resemble them both in their appearance and situa- 
tion ; the oviducts are so small as with great difficulty to be 
traced, and the clitoris is just large enough to be distinguished. 
When the eggs are formed, all these parts develope 
themselves. 
The ovaria became exceedingly vascular, and the yolks 
become conspicuous in all the stages of their increase, from 
the size of a pea to that of a walnut, and when arrived at that 
size, they pass into the oviduct. 
The number of yolks which are ready at any one time 
to pass into the oviduct, varies exceedingly in different fishes, 
E e 2 
