366 



COMPARATIVE ANATOMY 



wards the kidneys, and opens into a longitudinal canal. From the 

 latter the sperm passes through a second system of transverse canals 

 to the Malpighian capsules, and thence through the urinary tubules 

 into the urinogenital duct. 



The male generative apparatus of all Urodela and certain 

 Anura (comp. p. 354) corresponds in the main with that seen in 

 -Ceecilians, except as regards the form of the gonads : thus the testis 

 is either pointed at one or both ends (Fig. 279), or more or less 

 round or oval (Figs. 280, 292). 



In Rana, Bombinator, and Alytes the vasa efferentia of the testis become 

 gradually separated from the kidney : that is, they either open directly into 

 the urinogenital duct, without becoming connected with the urinary tubules 



Pig. 292. 



-Testis and Anterior End of Kidney op Rana escuhnta. 

 (Semidiagramjnatic. ) 



-Ho, testis ; q, q, transverse canals of the testicular network, which give rise to 

 blmd processes a,t i -f ; L, longitudinal canal of the testicular network from 

 which the interrenal network (C, C) arises ; xV, kidney ; Ur, urinogenital 

 duct. 



(Rana, Fig. 292), or the greater number of the posterior canals end 

 Mindly, while only the anterior ones are directly connected with the 

 urinogenital duct (Bombinator). In Alytes the relations of the generative 

 ducts require further investigation. 



Miillerian ducts are always present, but they always remam in a more or 

 less rudimentary condition in the male, and lie along the outer border of the 

 kidneys m a similar position to those of the female. They may or may not 

 be provided with a lumen and apertures of communication with the body- 

 cavity and cloaca. 



Heimiqjhroditkm occasionally occurs amongst the Anura : only one case 

 (Triton tfeniatus) is known amongst Urodeles. A body attached to the 

 anterior end of the testis in various species of Toads ("Bidder's orcran ") is 

 apparently capable of giving rise to ova and spermatozoa. In the males of 

 Rana temporaria ova are at times developed, embedded within the sub- 



