Chap. XVIII. 
QUADRUMAXA. 
311 
in some degree probable that both sexes owe their 
elegant appearance to sexual selection. In the mous- 
tache-monkey (Cercopithecus cepJius) the general colour 
of the fur is mottled-greenisli, with the throat white ; in 
the male the end of the tail is chesnut ; but the face is 
the most ornamented part, the skin being chiefly bluish- 
grey, shading into a blackish tint beneath the eyes, 
with the upper lip of a delicate blue, clothed on the 
lower edge with a thin black moustache ; the whiskers 
Fig. 1 6. Cercopithecus Diana (from Brehm). 
