14 
MAMMALIAN ANATOMY 
kidney, but not a part of the urinary system. Remove the peri¬ 
toneal covering of the kidneys and from each kidney trace the 
ureter which extends posteriorly, dorsal to the parietal peri¬ 
toneum, as a slender duct which leads into the dorsal region of the 
urinary bladder near its posterior end. To demonstrate this 
relationship the urinary bladder must be drawn forward. Note 
the ventral location of the bladder, and that it lies mainly pos¬ 
terior to and with its anterior surface covered by, the parietal 
peritoneum. 
Open the pelvic cavity by cutting through .the pubic arch a 
little to one side of the symphysis, after first carefully pushing 
aside, in case the animal is a male, the organs which lie ventral 
to the arch. Lay the pelvic cavity as widely open as possible by 
forcibly spreading apart the two halves of the pelvic girdle, and 
examine the contents of the cavity from the side. 
Note that in the pelvic cavity there are no serous membranes, 
and that the organs lie in a packing of areolar and adipose tissue. 
This packing should be carefully removed until the contours of 
the various pelvic organs can be fully seen. The most dorsal 
of these is the rectum, which may now be traced to the anal 
orifice, while the most ventral is the urethra which leads from the 
bladder to the external orifice in the ventral wall of the deep depres¬ 
sion known as the urogenital sinus of the female, while in the male 
the urethra takes a much more extensive course through the whole 
length of the penis, to reach the orifice. 
The Reproductive System. —In the female find the very small 
oval ovary upon each side posterior to the kidney and supported by 
a reduplicature of the peritoneum known as the mesovarium. 
From near the ovary a funnel-shaped orifice leads into a tiny coiled 
tube, the uterine tube or oviduct, which in turn leads into the 
anterior end of the corresponding arm of the Y-shaped uterus. All 
of these structures are supported by the mesovarium, which thus 
corresponds to the “ broad ligament ” of the human female. Trace 
the two arms of the uterus to their union posteriorly into the 
median portion and note that this is located dorsal to the bladder 
and ventral to the rectum in the pelvic cavity, and thus like these 
organs is posterior to the parietal peritoneum. The uterus leads 
into the thinner walled and more distensible tube, the vagina, 
