20 VETERINARY OBSTETRICS. 
The Meatus Urinarius. 
This is the external opening of the female urethra, 
and is found on the floor of the vulva about five inches 
from its external opening, but the distance varies in 
different animals. The opening is guarded by a fold 
of mucous membrane attached to the floor and sides of 
the vulva, having its free border placed in a backward 
direction. This membrane is believed to prevent the 
passage of urine into the vagina. In the Cow, imme- 
diately behind the opening of the meatus, there is a 
small fossa about half an inch in depth, also guarded 
by a valve, the function of which is doubtful, but it 
frequently causes difficulty in passing the catheter in 
that animal, being mistaken for the meatus. 
About one inch from the external opening of the 
vulva in the Cow, are situated some almond-shaped 
conglomerate glands whose ducts unite to form a sinus, 
by which the secretion from the glands is thrown into 
the vulva about half an inch, from the external border, 
These glands are only active at the period of cestrum, 
and are believed to secrete a fluid having a character- 
istic odor, which seems to attract the opposite sex at 
this period. 
In the female Pig, there is no vulvo-vaginal 
membrane guarding the opening of the meatus, and in 
this animal the clitoris is only rudimentary, and often 
absent altogether. 
In the female Cat, there is in the clitoris a small 
cartilaginous body which has not been seen in any 
other of the domestic animals, and has been believed 
