48 SEXUAL DIMORPHISM 



on the skin of the sides of the snout, which was already 

 nearly or quite hairless. 



It is a curious fact that the greatest resemblances to the 

 beard in the Caucasian races, and to the long hair of women, 

 are to be found, not among the anthropoid apes, but in two 

 species of the Platyrhini or American apes, whose dentition 

 differs from that of man. 1 Pithecia Satanas, the Couxia, has 

 a magnificent beard much larger in the male than in the 

 female, while in another species, the Yarke\ the head of the 

 female is adorned with elongated hair. It would be of great 

 importance to know whether the habits of these two species 

 are such as to involve any special stimulation of the hair 

 follicles on the chin in the one case, on the head in the other. 



The majority of anthropologists agree in the conclusion 

 that all the races of man are descended from a single species. 

 The most important characters of man as distinguished from 

 apes are the erect attitude, the more developed brain and 

 skull, the specialised hand, and the faculty of speech. It 

 appears prima facie very improbable that all these characters 

 were evolved independently in descendants of more than one 

 species of anthropoid ape. But, on the other hand, simi- 

 larities of almost if not quite equal importance are common 

 not merely to the species but to the genera of anthropoid 

 apes. The Gorilla, Orang, and Gibbon resemble one another 

 in the characters adapting them to an arboreal existence 

 much in the same way as the main races of man resemble 

 one another in the human peculiarities mentioned above. 

 Yet no one suggests that the former are races of one species. 

 There is certainly some foundation for the supposition which 

 has been suggested by some anthropologists, that the Negro is 

 more closely allied to the Gorilla than to the Caucasian race 

 of man. It is conceivable that distinct species of ape in 

 former geological periods gave rise independently to the 



1 See Man and Apes, by St. George Mivart, London, 1873, p. 59. 



