308 
SEXUAL SELECTIOX: MAMMALS. 
Part II.. 
arrangement of the hair on the face and head in several 
species. It is scarcely conceivable that these crests of 
hair and the strongly-contrasted colours 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 
Cercopithecus 'petaurista (fig. 75) is black, the whiskers 
and beard being white, with a defined, round, wffiite 
spot on the nose, covered with short white hair, which 
gives to the animal an almost ludicrous aspect. The 
Semnopithecus 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 eethiops is grotesque, with its black face, white 
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 the coloured plates in Geoffrey St. -Hilaire and 
F.. Cuvier, ‘Hist. Nat. des Mammiferes/ tom. i. 1824. 
