348 



The Descent of Man. 



Paet II. 



Amphibians. 



Urodela. — I will begin with the tailed amphibians. The sexes 

 of salamanders or newts often differ much both in colour and 

 structure. In some species prehensile claws are developed on 

 the fore-legs of the males during the breeding-season : and at 

 this season in the male Triton pulmipes the hind-feet are pro- 

 vided with a swimming-web, which is almost completely- 

 absorbed during the winter ; so that their feet then resemble 



Fig 32. Tritun crista'ua (half natural size, from B U's ' British Reptiles '). 

 Upper tigure, male during the brceding-s.-asun ; lower figure, feuiale. 



those of the female.'" This structure no doubt aids the male 

 in his eager search and pursuit of the female. Whilst courting 

 her he rapidly vibrates the end of his tail. With our common 

 newts ('Iriton puin-tatus and ej-htntiis) a deep, much indented 

 crest is developed along the back and tail of the male during the 

 breeding-season, which disappears during the winter. Mr. St. 

 George Mivart informs me that it is not furnished with muscles, 

 and therefore cannot be used for locomotion. As during the 

 season of courtship it becomes edged with bright colours, there 

 can hardly be a doubt that it is a masculine ornament. In 

 many species the body presents strongly contrasted, though 

 lurid tints, and these become more vivid during the breeding- 

 season. The male, for instance, of our common httle newt 

 (Triton punctuttis) is " brownish-grey above, passing into yellow 



" Boll, 'Hktory of British Reptiles,' 2iid edit. 1819, pp. 156-1.j9. 



