EVOLUTION OF MAN 43 



lately some data concerning the inheritance of such 

 features in crosses between Canadian Indians and 

 Europeans, but it seemed to me that he found all the 

 Indian characters segregating together in one indi- 

 vidual, and that this could only occur in a much 

 smaller proportion of cases than he stated. His 

 evidence would have been more convincing if he had 

 dealt with single marked features and proved that 

 they segregated.* In negro crosses we have no satis- 

 factory evidence of segregation in any character, 

 whether adaptive or otherwise.! 



A word or two may be devoted to the considera- 

 tion of Darwin's suggestion that sexual selection may 

 account for the non-adaptive character of human 

 races. I have shown that where the characters are 

 confined to one sex selection cannot be the cause 

 of this limitation. Where a character is already 

 unisexual, however, it may vary and remain uni- 

 sexual, as, for instance, in the human beard. The 

 question, then, is whether selection by the female is 

 required to account for a difference in the beard, or 

 whether the mutation might not establish itself 

 without selection. In deer the antlers differ in 

 different species in size and shape, and it could 

 scarcely be suggested that the particular size and 

 shape in a given species was due to the fact that they 



* He did, however, state that segregation occurs between the 

 blue eye, fair complexion, and light hair of a Scotsman, and the black 

 eye, olive skin, and black hair of the Red Indian. — Natutr, Nov. 7, 

 1907, p. 9, and Proceedings Royal Society of Medicine, Vol. II., 

 No. 3, p. 124. Jan. 1909. 



t This, of course, does not now hold true. See pedigree No. 3 

 in this Journal, page 24. — TIte Editor. 



