CHAPTER III 



reptiles and amphibia 



Reptiles 



The sexual differences of reptiles, as far as they are described 

 by Darwin, support in a very remarkable and convincing 

 manner the arguments I am maintaining. In reptiles as in 

 birds the fertilisation of the ova is internal, in other words 

 the sexes unite in breeding, although the males and females 

 do not generally associate together for such long periods, 

 and, except in rare cases and to a slight degree, no care is 

 bestowed on eggs or young. In the Lacertilia, however, the 

 males fight with one another for the possession of the 

 females, and in this Order we find the most strongly developed 

 unisexual characters. In many instances these characters 

 are in the form of outgrowths of the head, which serve as 

 weapons, and which, in their function and in their origin, 

 are somewhat similar to the horns of the Ungulata among 

 mammals. 



In the genus Ceratoplwra the male bears on the end of his 

 snout a simple conical projection, which is flexible, covered 

 with scales, and apparently capable of erection. This 

 appendage seems to be an outgrowth of the skin, and not to 

 contain any outgrowth of the bone of the jaw. It is rudi- 

 mentary in the female. In another species a terminal scale 



