308 SEXUAL SELECTION : MAMMALS. Part IL 



arrangement of tlie hair on the face and head in several 

 species. It is scarcely conceivable that these crests of 

 hair and the strono-lv-contrasted colonrs of the fur and 

 skin can be the result of mere variability without the 

 aid of selection ; and it is inconceivable that they can 

 be of any ordinary use to these animals. If so, they 

 have probably been gained through sexual selection, 

 though transmitted equally, or almost equally, to both 

 sexes. With many of the Quadrumana, we have addi- 

 tional evidence 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. 



With respect to the strange manner in which both 

 sexes of some species are coloured, and of the beauty 

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

 Cercoyitlieciis petaurista (fig. 75) is black, the whiskers 

 and beard being white, with a defined, round, white 

 spot on the nose, covered with short white hair, which 

 gives to the animal an almost ludicrous aspect. The 

 Semnovitliecus frontatus likewise, has a blackish face 

 with a long black beard, and a large naked spot on 

 the forehead of a bluish-white colour. The face of 

 Macacus lasiotus is dirty flesh-coloured, with a defined 

 red spot on each cheek. The appearance of Cerco- 

 cebus f^thioys is grotesque, with its black face, wdiite 

 whiskers and collar, chesnut head, and a large naked 

 white spot over each eyelid. In very many species, the 

 beard, whiskers, and crests of hair round the face are of 

 a different colour from the rest of the head, and when 

 different, are always of a lighter tint,** being often pure 



*•* I observed this fact in the Zoological Gardens; and numerous 

 cases may be seen in tie coloured plates in Geoifroy St.-Hilaire and 

 F. Cuvier, ' Hist. Nat. des Mammiferes,' tcm. i. 1824. 



