MALE GENITAL ORGANS OF THE DOG 593 
The prepuce has a narrow orifice, around which there are stiff hairs. The 
cavity is very long, and is partially divided by a circular fold into a posterior narrow 
part and a much wider anterior part. The lining membrane of the posterior part is 
papillated, and is in close contact with the penis; it contains numerous lymph 
nodules, the largest of which occur in the fundus. In the dorsal wall of the wide 
part there is a circular opening which leads into a cul-de-sac, the preputial diver- 
ticulum. This pouch is ovoid in form (when distended), and varies greatly in size 
in different subjects. It extends for the most part backward over the narrow part 
of the prepuce. Its cavity is partially divided by a narrow septum. It contains 
usually decomposing urine and macerated epithelium, which have a characteristic 
and very unpleasant odor. Concrements have been found in it. 
Oehmke found that a cast of the pouch in a Yorkshire boar weighing about, 500 pounds 
measured 9 cm. in length, 124 em. in breadth, and 6 em. in height. The opening into the pre- 
puce will admit two fingers in the adult, but is ordinar ily closed by folds of the liming membrane. 
The sac is much smaller in animals which were castrated young, and the opening is vertical and 
further back; in them it is often empty or contains only a ‘little clear urine. _The pouch is gland- 
less, but contains many small lymph nodules; it is covered by a layer of striped muscle which is 
mainly derived from the homologue of the protractor of the prepuce of ruminants. 
The urethra has a very long pelvic part (ca. 15 to 20 em. long in the adult); 
it is covered (with the pars disseminata of the prostate) by a thick urethral muscle, 
except dorsally, where there is a dense fibrous layer. Surrounding the mucous 
membrane there is a rich venous plexus, which is regarded as a stratum cavernosum. 
Outside of this the pars disseminata of the prostate is easily distinguished on cross- 
section by its yellow color. The prostatic ducts are numerous and small. The 
ductus deferentes and the excretory ducts of the vesiculz seminales have slit-like 
openings close together in small diverticula on either side cf the colliculus seminalis. 
The latter has the form of a round prominence. A small uterus masculinus may 
occur in the colliculus between the ducts, but it is often absent. There is a distinct 
bulb at the root of the penis. It has a dense covering, which in part resembles 
fibro-cartilage. The erectile tissue here is highly developed. The cavernous 
spaces are large, and the trabecule contain much unstriped muscle; between the 
spaces there are numerous arteries. The penile part is of small caliber, and is 
surrounded by erectile tissue which, however, does not extend to the extremity of 
the penis. 
MALE GENITAL ORGANS OF THE DOG 
The scrotum is situated about half way between the inguinal region and the 
anus. The skin covering it is pigmented and is covered sparsely with fine hairs. 
The raphé is not very distinct. 
The testicles are relatively small, and have a round-oval form. The long 
axis is oblique, and is directed upward and backward. The mediastinum testis 
is central and is well developed. The epididymis is large, and is closely attached 
along the dorsal part of the lateral surface of the testicle. 
The spermatic cord and the tunica vaginalis are long; they cross the side of 
the penis very obliquely. The upper end of the tunic is sometimes closed, so that 
there is then no vaginal ring. The ductus deferentes have narrow ampulle. 
The vesicule seminales are absent. 
The prostate is relatively large; it is yellowish in color, dense in structure, 
and lies at or near the anterior border of the pubis. It is globular, and surrounds 
the neck of the bladder and the urethra at their junction. A median furrow indi- 
eates a division into two lateral lobes. The capsule and stroma contain a large 
a a unstriped muscle. The ducts are numerous. Lobules of prostatic 
