l8o ELEMENTS OF MAMMALIAN ANATOMY. 



ova occur near the close of the first year of the cat's life 

 and new ones probably continue to mature during the 

 next ten years. The discharge of the ova from the ovary 

 is accompanied by a constitutional disturbance, during 

 which an extra amount of blood is sent to the sexual 

 organs, and the sexual appetite becomes very marked. 

 In the human species this disturbance occurs about every 

 twenty-eight days. Mature ova occur in the human ovary 

 between the thirteenth and forty-eighth years. 



The mammary glands of the adult female cat reach 

 their full development when it gives birth to young. 

 They may be seen by carefully removing the skin from 

 the ventral aspect of the body, when they will appear 

 somewhat like a thin layer of adipose tissue extending 

 from near the axilla to the pubic symphysis. There are 

 four teats or nipples on each side. In some mammals the 

 nipples are less numerous and confined either to the 

 thoracic or inguinal region. In the elephant, Chiroptera, 

 and Primates there are but two nipples, and they are 

 thoracic. In most Ungulates the nipples are inguinal. 



THE MALE REPRODUCTIVE SYSTEM. 



The organs of generation in the male consist of the 

 testes, the ducts leading from the testes to the urethra, 

 the prostate gland, Cowper's gland, and the penis. 



The testes are two in number, contained in a pouch of 

 integument called the scrotum, which hangs beneath the 

 anus. Internally the scrotum is divided into two cham- 

 bers. By dissecting away the adipose tissue covering 

 the spermatic cord in the inguinal region (Fig. 51) it 

 may be seen that the cord and the testes are enveloped 

 by a tough sheath. This is composed of cremasteric 

 fascia derived from the aponeurosis of the external ob- 



