THE UROGENITAL SYSTEM 105 



dilute the secretion from the testicles, adding volume to it, and thus 

 affording a greater opportunity for it to reach the ovum. 



The penis is largely composed of erectile tissue — the corpus 

 cavernosum. The organ extends from the ischial arch, where it is 

 firmly attached, forward between the thighs. It has at the free 

 end a covering of skin, called the prepuce or sheath (Fig. 33). 

 The inner layers of the prepuce are supplied with large seba- 

 ceous glands, the secretion of which has a tendency to collect here 

 and cause "foul sheath" unless washed out at intervals. When the 

 diverticulum of the fossa of the glans penis becomes filled with 

 smegma it causes the formation of a "bean," which sometimes 

 materially interferes with urination. The penis is the male copu- 

 latory organ. 



The urethra of the stallion is the long mucous tube which extends 

 from the bladder to the lower or anterior end of the penis. It 

 passes backward on the floor of the pelvis, turns around the 

 ischial arch, and then runs forward and downward, embedded in 

 the spongy tissue of the penis. The urethra conveys both the 

 urine and the semen. 



THE REPRODUCTIVE ORGANS OF THE MARE' 



The female genital organs are the two ovaries, the fallopian 

 tubes, the uterus, the vagina, the vulva, and the mammary glands 

 (Fig, 34). 



The ovaries are two in number, bean shaped, and much smaller 

 than the testicles, with which they are homologous. They are 

 situated about a hand breadth behind the corresponding kidney. 

 A fold of peritoneum attaches them loosely to the sublumbar 

 region. Embedded in the fibrous tissue of the substance of the 

 ovary are little masses of epithelial cells from which the graafian 

 follicles and eventually the ova develop. The functional value of 

 the ovaries is connected with the formation of the ovum or female 

 reproductive cell. 



The fallopian tubes are two tortuous passages, about 10 inches 

 long, that run between the layers of the broad ligaments. The 

 ovarian end of the tube is fringed or fimbriated, and expanded into 

 a funnel-like infundibulum for the purpose of catching the ova 



' Azoux models have been found especially useful to give the student a 

 blear conception ' of the structure and functions of the female generative 

 organs. 



