578 



GENITAL ORGANS OF THE STALLION 



— 1 



THE VESICUL^ SEMINALES 



The vesiculas seminales (Fig. 517) are two elongated and somewhat piriform 

 sacs, which he on each side of the posterior part of the dorsal surface of the blad- 

 der. They are partly enclosed in 

 "~^~^-_ the genital fold, and are related to 



the rectum dorsally. Their long axes 

 are parallel with the ductus def- 

 erentes and converge posteriorly. 

 Each consists of a rounded blind 

 end, the fundus; a middle, slightly 

 narrower part, the body ; and a pos- 

 terior constricted part, the neck or 

 duct. 



In the stallion they are about 

 six to eight inches (ca. 15 to 20 cm.) 

 long, and their greatest diameter is 

 about two inches (ca. 5 cm.); in 

 the gelding they are usually much 

 smaller.^ 



The vesiculse are chiefly retro- 

 peritoneal, but the fundus extends 

 forward into the genital fold and 

 hence has a serous covering. The 

 excretory duct (Ductus excretorius) 

 dips under the prostate, and opens 

 in common with or alongside of the 

 ductus deferens in a pouch of the 

 mucous membrane on the side of 

 the colliculus seminalis. 



Structure. — The wall, exclusive 

 of the partial serous coat, consists 

 of a fibrous adventitia, a middle 

 muscular coat, and a mucous lining. 

 The muscular coat is thickest at the 

 fundus, and consists of two planes 

 of longitudinal fibers with a circular 

 layer between them. The mucous 

 membrane is thin, and is arranged 

 in numerous folds and projections 

 which form a network; th§ spaces 

 so enclosed .present the openings of 

 tubulo-alveolar glands. The epithe- 

 lium is' columnar. The blood-supply 

 is derived- from the internal pudic 

 artery. 



Fig. 517. — Internal Genital Organs op Staluon; Dorsal 

 View. 



On left side urethral muscle has been removed over bulbo- 

 urethral gland. Cornua of uterus masculinus are indicated in 

 genital fold. The posterior limit of the peritoneum is shown 

 but not marked. 1, Round ligament of bladder; 2, lateral liga- 

 ment of bladder ; 3, bulbo-urethral gland. 



THE PROSTATE 



The prostate (Prostata) is a lobulated gland which lies on the neck of the 

 bladder and the begiiming of the urethra, ventral to the rectum. It consists of 



'1 Sometimes one or both of the vesiculse are very large in the gelding. The writer has seen 

 four cases in the dissecting room, three of which were bilateral, the other unilateral. The vesicula 

 resembled the urinary bladder in appearance and contained ataout a quart of thick, amber-colored 

 secretion. 



