548 THE DESCENT OF MAN. 



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 delicate 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 por- 

 tion is black.''' 



In these and many other monkeys, the beauty and singular 

 arrangement of their colors, and still more the diversified 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 orna- 

 ments. 



Sammaw- — 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, cour- 

 age, and pugnacity of the male, his special weapons of offense, 

 as well as his special means of defense, have been acquired or 

 modified through that form of selection which I have called 

 sexual. This does not depend 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. 



There is another and more peaceful kind of contest, in which 

 the males endeavor to excite or allure the females by various 

 charms. This is probably carried on in some cases by the power- 

 ful odors emitted by the males during the breeding-season; the 

 odoriferous glands having been acquired through sexual selec- 

 tion. Whether the same view can be extended to the voice is 

 doubtful, for the vocal organs of the males must have been 

 strengthened by use during maturity, under the powerful excite- 

 ments of love, jealousy or rage, and will consequently have been 

 transmitted to the same sex. Various crests, tufts, and mantles 

 of hair, which are either confined to the male, or are more de- 

 veloped in this sex than in the female, seem in most cases to be 

 merely ornamental, though they sometimes serve as a defense 

 against rival males. There is even reason to suspect that the 

 branching horns of stags, and the elegant horns of certain ante- 

 lopes, though properly serving as weapons of offense or defense, 

 have been partly modified for ornament. 



" I have seen most of the above monkeys in the Zoological Society's 

 Gardens. The description of the Semnopithecus nemaeus is taken from 

 Mr. W. C. Martin's 'Nat. Hist, of Mammalia," 1841, p. 4G0; see, also, 

 pp. 475, 523. 



