MAMMALS, 62? 



hair and the strongly contrasted colors of the fur and skin, 

 can be the result of mere variability without the aid of se- 

 lection; and it is inconceivable that they can be of use in 

 any ordinary way to these animals. If so, they have 

 probably been gained through sexual selection, though 

 transmitted equally, or almost equally, to both sexes. 



Fig. 73. Head of Semnopithecus comatus. Fig. 74. Head of Cebus capucinus. 



Pig. 75. Head of Ateles marginatus. Fig. 76. Head of Cebus vellerosus 



With many of the Quadrumana, we have additional evi- 

 dence of the action of sexual selection in the greater size 

 and strength of the males, and in the greater development 

 of their canine teeth, in comparison with the females. 



A few instances will suffice of the strange manner in 

 which both sexes of some species are colored and of the 

 beauty of others. The face of the Cercopithemis petaurista 



