THE UROGENITAL SYSTEM 



103 



felt. When either or both testicles fail to pass into the scrotum the 

 horse is said to be a cryptorchid or ridgling. A serous membrane, 

 the tunica vaginalis propria, closely envelops the testicle. It is a 



Fig. 32. — Internal genital organs of stallion, dorsal view: 1, Round liga- 

 ment of bladder; 2, lateral ligament of bladder; 3, Cowper's gland. The 

 branches of the uterus masculinus are indicated in the genital fold. (Sisson, 

 Anatomy of Domestic Animals.) 



reflection of the abdominal peritoneum. The testicles secrete the 

 spermatic fluid or semen. 



The scrotum is the sac in which the testicles are normally 

 enclosed. It has an outer layer of soft, oily skin, beneath which is 

 a strong fibrous layer. The tunica vaginalis communis Hnes the 



