SEXUAL SELECTION 713 



the upper lip of a delicate blue, clothed on the lower edge 

 with a thin black mustache; the whiskers are orange colored, 

 with the upper part black, forming a band which extends 

 backward to the ears, the latter being clothed with whitish 

 hairs. In the Zoological Society's Gardens I have often 

 overheard visitors admiring the beauty of another monkey, 

 deservedly called Cercopithecus diana (Mg. 78); the general 

 color of the fur is gray; the chesib and inner surface of the 

 forelegs are white; a large triangular defined space on the 

 hinder part of the back is rich chestnut; in the male 

 the inner sides of the thighs and the abdomen are deli- 

 cate fawn colored, and the top of the head is black; the 

 face and ears are intensely black, contrasting finely with 

 a white transverse crest over the eyebrows, and a long, 

 white, peaked beard, of which the basal portion is black." 

 In these and many other monkeys, the beauty and singu- 

 lar arrangement of their colors, and still more the diversi- 

 fied and elegant arrangement of the crests and tufts of hair 

 on their heads, force the conviction on my mind that these 

 characters have been acquired through sexual selection 

 exclusively as ornaments. 



Summary. — The law of battle for the possession of the 

 female appears to prevail throughout the whole great class 

 of mammals. Most naturalists will admit that the greater 

 size, strength, courage, and pugnacity of the male, his 

 special weapons of offence, as well as his special means of 

 defence, have been acquired or modified through that form 

 of selection which I have called sexual. This does not de- 

 pend on any superiority in the general struggle for life, but 

 on certain individuals of one sex, generally the male, being 

 successful in conquering other males, and leaving a larger 

 number of offspring to inherit their superiority than do the 

 less successful males. 



*' I have seen most of (;he above monkeys in Ihe Zoological Society's Gar- 

 dens. The description of the Semnopithecas nemcsus is taken from Mr. W. 0. 

 Uartin's "Nat. ISist. of Mammalia," 1841, p. 460; see, also, pp. 475, 523. 



