170 ELEMENTS OF MAMMALIAN ANATOMY. 
The mammary glands of the adult female cat reach 
their full development when it gives birth to young. They 
may be seen by carefully removing the skin from the ven- 
tral aspect of the body, when they will appear somewhat 
like a thin layer of adipose tissue extending from near the 
axilla to the pubic symphysis. There are four teats or 
nipples on each side. In some mammals the nipples are 
less numerous and confined either to the thoracic or inguinal 
region. In the elephant, Chiroptera, and Primates there 
are but two nipples, and they are thoracic. In most 
Ungulates the nipples are inguinal. 
THE MALE REPRODUCTIVE SYSTEM. 
The organs of generation in the male consist of the 
testes, the ducts leading from the testes to the urethra, the 
prostate gland, Cowper's gland, and the penis. 
The testes are two in number, contained in a pouch of 
integument called the scrotum, which hangs beneath the 
anus. Internally the scrotum is divided into two chambers. 
By dissecting away the adipose tissue covering the spermatic 
cord in the inguinal region (Fig. 51) it may be seen that 
the cord and the testes are enveloped by a tough sheath. 
This is composed of cremasteric fascia derived from the 
aponeurosis of the external oblique muscle, and of the tunica 
vaginalis. 
During the fetal life the testes lie in the abdominal cavity, 
and when they descend into the scrotum about the time of 
birth, a double layer of peritoneum is pushed down before 
them through the inguinal canal, forming a diverticulum 
whose blind end lies within the scrotum, while the con- 
stricted portion forms a channel for the vas deferens, 
spermatic nerve, and vessels. These three structures form 
the spermatic cord (Fig. 51). The fascia propria (tunica 
vaginalis communis) is inseparably united with the adjacent 
