SEXUAL SELECTION IN BIRDS. 381 



and that in so far as vigour may be a selected quality, it is 

 selected only incidentally to this, which, however, would often 

 be the case. 



In conclusion, I would urge that the facts here brought 

 forward by me, in regard to four different species of birds, are, 

 both singly and cumulatively, strongly in support of Darwin's 

 second great hypothesis of sexual selection, and I believe that, 

 as denial from the chair is replaced, or supplemented, by 

 evidence from the field, the views of that great naturalist 

 and reasoner will be triumphantly and often most strikingly 

 vindicated. 



