246 ANATOMY OF THE ABDOMEN. 



of the size and shape of a chestnut, situated near 

 the greater, and almost lying upon the spines of the 

 ischium. Both the larger and lesser prostates open by 

 numerous outlets into the urethra. There is no doubt 

 whatever that the secretions of all the parts we have just 

 named are assistants to the seminal fluid, but in what 

 degree or in what manner is not known. 



The spermatic cord consists of a covering of peritoneum, 

 the vas deferens, the cremaster muscle, arteries, veins, 

 nerves, absorbents, cellular tissue, and a slight fibrous coat 

 beneath the peritoneum, continuous with the tunica albu- 

 ginea testes. It begins at the internal abdominal ring, 

 passes through the inguinal canal, emerges through the 

 external abdominal ring, and is inserted into the posterior 

 part of the testicle. 



The penis is a firm body, two feet in length. The sheath, 

 which incloses it from view, is formed of the common in- 

 teguments, continued loosely from the scrotum to the 

 umbilicus, and marked in the middle during this course 

 by a raphe ; forming altogether a very extended envelope. 

 The outer fold of the sheath owes its bulk to a ring of 

 ligamentous substance, which is useful in keeping the 

 orifice open and firm : from this the reflected integuments 

 become thinner and more vascular, and are again reflected 

 over the glans penis, forming its prepuce. The sub- 

 stance of the penis is chiefly composed of two portions : 

 each of which are alike in structure, both being formed of 

 erectile tissue. The last tissue is flaccid, and occupies little 

 space when not erected ; but when the animal is under 

 sexual excitement, it becomes distended with venous 

 blood, and is then much increased in bulk, and very firm. 

 One of these bodies occupies the inferior portion of the 

 penis, or is situated beneath the urethra ; the other fills a 

 place superior to the urethra, or on the top of the organ. 

 At the extremity there is a bulb which appears distinct, but 

 which anatomy proves to be continuous with the lower 

 portion of erectile tissue, and which altogether is called the 

 corpus spungiosum. The upper division is named the 

 corpus cavernosum. 



The urethra is the canal, which is continued through the 

 body of the penis from the bladder to the point of the 

 organ. That portion encircled by the two prostate glands 



