Chap. XVIII.] 



QUADRUMANA. 



293 



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. 



i IM.'i Vt'A 



Fig 71.— Head of Semnopithecus comatus. Fig. 72.— Head of Cebus capucinus. 



Fig. 73.— Head of Ateles marginatus. 



Fig. 74— Head of Cebus vellerosus. 



With respect to the strange manner in which both 

 sexes of some species are colored, and of the beauty of 

 others, .a few instances will suffice. The face of the Cer- 

 copithecus petaurista (Fig. 75) is black, the whiskers and 

 beard being white, with a defined, round, white spot on 



