AMPHIBIANS. 395 



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 colors, there can hardly be a doubt that 

 it is a masculine ornament. In many species the body pre- 

 sents strongly contrasted, though lurid tints, and these 

 become more vivid during the breeding-season. The male, 

 for instance, of our common little newt (Triton punctatus) 

 is " brownish-gray above, passing into yellow beneath, 

 which in the spring becomes a rich bright orange, marked 

 everywhere with round dark spots." The edge of tlie crest 



Fig. 32. Triton cristatus (half natural size, from Bell's " British Reptiles "). 

 Upper figure, male during the breeding-season; lower figure, female. 



also is then tipped with bright red or violet. The female 

 is usually of a yellowish-brown color with scattered brown 

 dots, and the lower surface is often quite plain.* The 

 young are obscurely tinted. The ova are fertilized during 

 the act of deposition, and are not subsequently tended by 

 either parent. We may therefore conclude that the males 

 have acquired their strongly-marked colors and ornamental 

 appendages through sexual selection; these being transmit- 

 ted either to the male offspring alone, or to both sexes. 



Anura or Batrachia. With many frogs and toads the 

 colors evidently serve as a protection, such as the bright 



*Bell, "History of British Reptiles," 2d edit., 1849, pp. 146, 151. 



