54 THE GENESIS OF SPECIES. [Chap. 



assume that this permanent change of conditiuns was 

 accidentally synchronous with the change of structure, we 

 have a coincidence of very remote probability indeed. Bufe 

 if, again, we accept the presence of some harmonizing law 

 simultaneously determining the two changes, or connecting 

 the second with the first by causation, then, of course, we 

 remove the accidental character of the coincidence. 



Again, how explain the external position of the male 

 sexual glands in certain mammals? The utility of the 

 modification, when accomplished, is problematical enough, 

 and no less so the incipient stages of the descent. 



As was said in the first chapter, ^Ir. Darwin explains the 

 brilliant plumage of the peacock or the humming-bird by 

 the action of sexual selection ; the more and more brilliant 

 males being selected by the females (attracted by this 

 brilliancy) to become the fathers of the next generation, 

 to which generation they tend to communicate their own 

 briglit nui)tial vesture.^ But there are peculiarities of 

 colour and of form which it is not possible to account for 



^ III the oi)inioii of the author of this book, ]\Ir. Darwin has utterly 

 failed to show (in his most recent work) that sexual selection acts effica- 

 ciously in modifying species, if indeed it acts at all. Certainly, even in 

 birds soxual peculiarities occur which cannot be due to sexual selection ; 

 as, e.g. the colouring of the hisitlc of the mouth in the Ilornbill (Burrros 

 bicornis), an<l the excess in size, in male pigeons, of the wattle of the 

 "Carrier" and the crop of the "Pouter," an excess not arising " from, 

 Imt rather in o}»i)osition to, the wishes of the breeder." Mr. Darwin him- 

 self tells us, " I have received long letters on this subject from Messrs. 

 Hewitt and Tegetmeier, and almost an es.say from the late Mr. Dreut. It 

 will be admitted by every one that thes<' gentlemen, so well known from 

 their ]tublished works, are careful and experienced observers. They do 

 not believe that the females jirefer certain niales on account of the beauty 

 of their plumage." . . . " Mr. Tegetmeier is convinced that a gume-cock, 

 though disfigured by being dubbed with his hackles tiimmed, would be 

 accepted a.s readily as a male retaining all his natural ornaments." — Descent 

 of Man, vol. ii. p. 117. 



