208 THE EVOLUTION OF MAN. 



partially lost their original coat of hair in consequence of 

 adaptation.^^^ 



The form of Adaptation which has degraded the growth 

 of hair on most parts of the human body, while preserving 

 it, or even greatly developing it, on certain parts, was, in all 

 probability, sexual selection. As Darwin has very clearly 

 shown in his work on " The Descent of Man/' sexual selec- 

 tion has had especially great influence in this respect. In 

 consequence of the male Anthropoid Apes, in selecting a 

 pai'tner, preferring those females which were least hairy, 

 and in consequence of the females preferring those suitors 

 which were distinguished by peculiarly fine beard or head- 

 hair, the general hirsuteness of the body was gradually 

 degraded, while the beard and the hair of the head were 

 advanced to a higher degree of perfection. Climatic con- 

 ditions, and other circumstances unkno\vn to us, may, 

 however, also have promoted the loss of the hairy coat. 



In proof of the assertion that the hairy covering of 

 Man is directly inherited from the Anthropoid Apes, we 

 find, according to Darwin, a curious evidence in the direc- 

 tion, otherwise inexplicable, in which the rudimentary 

 hairs lie on our arms. Both on the upper and on the 

 lower arm the hairs are directed towards the elbow, where 

 they meet at an obtuse angle. Except in Man, this striking 

 arrangement occurs only in the Anthropoid Apes, the Gorilla, 

 Chimpanzee, Orang, and several species of Gibbons. In 

 other Gibbons the hairs of both the lower and the upper arm 

 are directed towards the hand, as in other Mammals. This 

 remarkable peculiarity of Anthropoids and of Man can 

 only be explained on the assumption that our common ape- 

 like ancestors were accustomed, as they are even now, 



