ABDOMINAL VISCERA OF THE HORSE. 83 
thrown into longitudinal folds. It is antero-superiorly raised by 
the sub-mucous tissue into a permanent ridge, termed the crest 
of the urethra or verumontanum. This has a depression about 
its middle, and on each side are the elliptical orifices of the 
ejaculatory ducts, surrounded by the openings of the prostatic 
ducts. Posteriorly and laterally are little papillated projections 
pierced by ducts emanating from Cowper’s glands. These tubular 
processes are arranged in two parallel lines longitudinally to the 
course of the urethra. 
The pelvic portion of the urethra is supplied with blood from 
the internal pudic, and the veins empty into the vessel of the 
same name. Its nerves are derived from the two last sacral 
and accompanying sympathetic filaments. 
The lymphatics of the pelvic urethra are similarly disposed 
to those of the bladder. 
Generative Organs. 
The last division of our subject is that of the abdominal gene¬ 
rative organs, only a part of the generative system, and consisting 
in the vasa deferentia, vesiculse seminales, prostate and Cowper’s 
glands. 
Vasa Deferentia. 
There are two vasa deferentia, one from each testicle, for the 
passage of semen to seminal reservoirs. 
The vas deferens arises from the posterior part of the epidi¬ 
dymis or globus minor, passing through the inguinal canals, and 
reaching the abdomen; it is situated in the sub-serous tissue, 
taking a course upwards, backwards, and inwards, to reach the 
brim of the pelvis; then, crossing the course of the ureters, it gets 
on to the bladder, where it is dilated, and forms the bulbous 
portion. 
Its attachments are serous and cellular to the various parts 
mentioned, whilst its posterior part is connected with the 
urethra. 
The vas deferens is related, in its course from the inguinal 
canal, to the bladder, after it leaves the constituents of the cord, 
with the parietes of the abdomen ; crossing the under surface of 
the iliac vessels, and reaching the bladder on the inner side of 
the ureter; also lying internally to the seminal vesicles, and the 
terminating portion being covered by the prostate. 
The structure of the vas deferens is similar throughout, with 
the exception of the greater thickness of its coats at the bulbous 
portion, being thinnest where it contributes to form the ejacu¬ 
latory duct. 
