224 



ESSENTIALS OF ZOOLOGY 



the tubules, and the blood is gathered and discharged by the 

 renal veins. The tubules of the kidney all open into the 

 mesonephric duct, which is the ureter. It runs down the outer 

 edge of the kidney and, reaching the cloaca, opens separately 

 from its neighbour on the dorsal wall. The anterior end of 

 the genital ridge, in degenerating, forms the rudiment of the 

 fat body, which undergoes expansion in the adult as conspicuous 

 lobed yellow bodies placed in front of the kidneys. 



In the male the testes are oval yellow bodies. The sperms 

 liberated from the walls of the tubules are conveyed from the 



Int. open, 

 oviduct 



Corp. ad. 



Corp. ad. 



Testis 



Vas. effer. 



Adrenal 



Sent. ves. 



Ureter 



Bladder. 

 Cloaca 



FIG. 113. Male (left) and female (right) reproductive organs. 



testes by a series of vasa efferentia on the inner anterior aspect 

 of the kidney. They are conveyed into the mesonephric 

 duct, which, in addition to acting as a ureter, is a vas defer ens. 

 In the male, moreover, the vas deferens is produced by a series 

 of small ducts into a triangular-shaped body on its lateral 

 surface. This is the seminal vesicle. 



In the female the ovaries are large irregular masses con- 

 taining eggs at all stages of development. At the breeding 

 season many of the eggs become ripe, and are shed into the 

 peritoneal cavity. They are conveyed forwards to the small 

 opening of the oviduct. The two openings lie close together 

 on each side of the oesophagus, and lead into the long 



