Epididymis ^-^ 

 Testis^ ^ 



Ureter 



Prostate 

 gland 



Urethra 



Cowper's 

 gland 



Penis 



Fig. 5.1. The reproductive system of the cat. 

 A, in the male; /i, in the female. (Redrawn 

 with modifications from J. Reighard and H. 

 S. Jennings, Anatomy of the (Jat, copyright 

 1901 by Henry Holt and Co., printed by 

 permission.) 



Ostium 



Fallopian 

 tube 



Ureter - 



Ovary 



Horn of 

 j / / uterus 



Body of 

 uterus 



-Vagina 



unrelated, and we shall be concerned here with only the reproductive or 

 genital system. In the vertebrates, as in the majority of animals, there are 

 typically two sexes; individuals are either male or female (p. 208). Both 

 gonads and ducts differ in the male and female reproductive systems. 



In male fishes and frogs the two gonads, or testes, are suspended by 

 mesenteries, the mesorchia, from the dorsal surface of the pleuroperitoneal 

 cavity ventral to the excretory organs which are mesonephroi (p. 57). In 

 reptiles and birds the testes are suspended near the metanephroi, or kidneys, 

 but in male mammals the gonads are located posterior to the kidneys and in 

 many sp)ecies descend until they lie outside the peritoneal cavity in the 

 scrotum. The testis is essentially a mass of small seminiferous tubules, along 

 the walls of which the primordial germ cells are found (p. 133). At the time 

 of sexual maturity, numerous spermatozoa fill the cavities of the seminiferous 

 tubules, which are continuous with the reproductive ducts. The fishes and 

 frogs have numerous small ducts, the ductus eflFerentes (vasa efferentia), which 

 are continuous with the seminiferous tubules in the testis and also with the 

 excretory tubules. In such animals spermatozoa pass from the tubules of each 

 testis to the ductus efferentes, which are located in the mesorchium, and into 

 the excretory tubules. Thence, the path to the outside is by way of the ex- 

 cretory duct and cloaca, and the male germ cells are shed from the body 

 through the anus. In reptiles, birds, and mammals, the spermatozoa no 

 longer pass through the excretory organs but leave each testis through a 

 coiled duct, the epididymis. This is continuous with a ductus deferens (vas 



129 



