156 



ZOOLOGY. 



tube, the ureter, the pair of which open separately into the 

 cloaca. 



19. Tiro-genital Organs: Male (fig. 78). The condition 

 in the male is more difficult to compare with the rabbit's 



at first sight. 

 The testes 

 occupy their 

 primitive posi- 

 tion in the body 

 cavity, and are 

 white bodies, 

 usually dappled 

 with black pig- 

 ment. Vasa... 

 efferentia run 

 from them to 

 the internal 

 border of the 

 anterior part of 

 the kidney, 

 which answers, 

 therefore, to 

 the rabbit's 



Pig. 78. UROGENITAL ORGANS OF MALE FROG. epldidymiS. 



(After Howes, .altered.) Thus the kid- 



ney (which is 



similar to that of the female) is not simply a lenal- 

 excretory organ, but also serves to transmit the sper- 

 matozoa. Similarly its duct is not merely an ureter, 

 but rather a uro-genital duct; into it a seminal vesicle, 

 which is especially large in early spring, opens. This, the 

 permanent condition of the frog, corresponds, as we shal 

 see when we come to study development, to temporary 

 embryonic stages of the rabbit. In front of the gonad in 

 both sexes is a fat-body (corpus adiposum), which acts as a 

 fat store against the time of hibernation. There is no penis 

 in the male, fertilisation of the ova occurring as they are 

 squeezed out of the female by the embracing fore limbs of 

 the male. The male has a pad, black in early spring, 



Of 

 *!. &C/CT3 



