322 Darwin, and after Darwin. 



in drawing any such inference [i.e. as to utility] when we see 

 the skin on the head of the clean-feeding male Turkey is 

 likewise naked \" 



Similarly, in the Descent of Man it is said : — 



" Variations of the same general nature have often been taken 

 advantage of and accumulated through sexual selection in re- 

 lation to the propagation of the species, and through natural 

 selection in relation to the general purposes of life. Hence, 

 secondary sexual characters, when equally transtnitted to both 

 sexes, can be distinguished from ordinary specific characters, 

 only by the light of analogy. The modifications acquired 

 through sexual selection are often so strongly pronounced 

 that the two sexes have frequently been ranked as distinct 

 species, or even as distinct genera "." 



As Mr. Wallace does not recognize sexual selection, he 

 incurs the burden of proving utility (in the life-preserving 

 sense) in all these " frequently " occurring cases where there 

 are such " strongly pronounced modifications," and we have 

 already seen in the text his manner of dealing with this 

 burden. But the point here is, that whether or not we 

 accept the theory of sexual selection, we must accept 

 it as Darwin's opinion — first, that in their beginnings, as 

 specific characters, these sexual modifications were often 

 of a merely '^general nature" (or without reference to 

 utility even in the life-embellishing sense), and only after- 

 wards " have often been taken advantage of and accumu- 

 lated through sexual selection " : and, secondly, that " we 

 know they have been acquired in some instances at the 

 cost not only of inconvenience, but of exposure to actual 

 dangers '." 



We may now pass on to some further, and even stronger, 

 expressions of opinion with regard to the frequent inutility of 

 specific characters. 



' Origin of Sfecies, pp. 157-8. 



' Descent of Man, p. 615. " Ibid. 



