MAMMALS. 629 



ludicrous aspect. The Semnopitliecus frontatus likewise 

 has a blackish face with a long black beard, and a large 

 naked spot on the forehead of a bluish- white color. The 

 face of Macacus lasiotus is dirty flesh-colored, with a 

 defined red spot on each cheek. The appearance of 

 Oercocebus cetliiops is grotesque, with its black face, white 

 whiskers and collar, chestnut 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 color from the rest of the head, and, when differ- 

 ent, are always of a lighter tint,* being often pure white, 

 sometimes bright yellow or reddish. The whole face of the 

 South American Brachyurus calvus is of a " glowing 

 scarlet hue;" but this color does not appear until the ani- 

 mal is nearly mature, f The naked skin of the face differs 

 wonderfully in color in the various species. It is often 

 brown or flesh-color, with parts perfectly white, and often 

 as black as that of the most sooty negro. In the Brachyu- 

 rus the scarlet tint is brighter than that of the most blush- 

 ing Caucasian damsel. It is sometimes more distinctly 

 orange than in any Mongolian, and in several species it is 

 blue, passing into violet or gray. In all the species known 

 to Mr. Bartlett, in which the adults of both sexes have 

 strongly colored faces, the colors are dull or absent during 

 early youth. This likewise holds good with the mandril 

 and rhesus, in which the face and the posterior parts of the 

 body are brilliantly colored in one sex alone. In these 

 latter cases we have reason to believe that the colors were 

 acquired through sexual selection; and we are naturally led 

 to extend the same view to the foregoing species, though 

 both sexes when adult have* their faces colored in the same 

 manner. 



Although many kinds of monkeys are far from beautiful 

 according to our taste, other species are universally ad- 

 mired for their elegant appearance and bright colors. The 

 Semnopitliecus nernceus, though peculiarly colored, is de- 

 scribed as extremely pretty; the orange-tinted face is sur- 

 rounded by long whiskers of glossy whiteness, with a line of 



* I observed this fact in the Zoological Gardens; and many cases 

 may be seen in the colored plates in Geoffrey St.-Hilaire and F, 

 Cuvier, " Hist. Nat. des Mainmi feres," torn, i, 1824. 



f Bates, " The Naturalist on the Amazons/' 1863, vol. ii, p, 310. 



