354 



THE VERTEBRATE BODY 



there are two small white testes, near the anterior end of the kidneys, 

 that produce sperms. These travel through delicate little tubules, the 

 vasa efferentia, into and through the kidneys and to the urogenital duct 

 which lies along the lateral side of the kidneys. Thus this duct serves 

 as both a ureter and a sperm duct. In some frogs this duct enlarges and 

 forms seminal vesicles just before it enters the cloaca. The sperms are 

 stored in these seminal vesicles before ejaculation. 



In the female the ovaries are found at about the same location as are 

 the testes in the male. They may be greatly enlarged so that they almost 



Seminal vesicles 

 Vas deferens 

 Urinary bladder 



Ejacu/afory ducts 



Prostate gland 



Urethra 



Corpora cavernosa 



Cowpers gland 



Penis 



Epididymis 



Prepuce 

 Glans 

 Testis 

 Scrotum 



Fig. 24.5. The male reproductive system. 



fill the entire coelom just prior to the sexual season. At other times they 

 will not be as large as the kidney. As the sexual season approaches, the 

 eggs mature and break out of the ovary into the coelom. At the anterior 

 end of this cavity is the opening to the oviduct, the ostium. The ostium 

 is funnel-shaped and, by some means, the eggs are attracted to this open- 

 ing, enter in and pass down the long coiled oviduct to a posterior en- 

 largement, the uterus, where they are stored. During the breeding 

 season the uteri and the oviducts will be greatly distended with eggs. 

 These are shed and fertilized as previously described. 



When we come to compare these systems with those found in human 



