THE HORNS AND ANTLERS OF RUMINANTS. 243 



vigorous males take forcible possession;* and, even were it 

 otherwise, the struggle for life would render the charm of useless 

 ornament inoperative. Complex cranial weapons have survived, 

 therefore they have once been useful, though sexual selection 

 leaves their utility unexplained. 



Equal difficulties arise, on the hypothesis, from the con- 

 sideration of frontal weapons in respect of sex. A theory of 

 horns and antlers, which finds their origin and purpose in the 

 sexual strife of rival males, requires the normal limitation of 

 such weapons to the sex for whose benefit they were primarily 

 developed and hy whose combats they have been conditioned 

 through time. Their normal presence in the females of half the 

 genera, representing all the families, of surviving ruminants which 

 exhibit them, argues their mutual utility, and thence a wider 

 purpose with a common origin. In other words, structural 

 characters which are present in both sexes, whether partially or 

 universally, possess a functional importance common to either 

 sex, or they do not. If they are evidently useful, there is a 

 strong presumption that they owe their existence to a primary 

 adaptation for the common purpose, with which sexual selection, 

 whether by male combat or by female choice, can have absolutely 

 no concern. If they are useful to the males only, their enduring 

 presence in the females unquestionably conflicts with the retro- 

 gressive principle of natural selection, which promotes the 

 degradation and disappearance of superfluous and wasteful 

 organs. Darwin touched here an aspect of the problem which 

 was vital to his theory as a whole, and cut the knot with 

 Alexander's sword. Carrying his argument into the wide battle- 

 ground of inheritance, he reached the conclusion that characters 

 originally proper to either sex might be transmitted to the same 

 sex, or to both, according to the form of inheritance assumed in 

 transmission, and independently of natural selection. f To this 

 conclusion, as applied to the presence or absence of frontal 



* The instance of a Bed-deer hind referred to by Darwin is a case not of 

 choice on the part of the female, but of chance on the part of an inferior 

 male, while his superior is engaged elsewhere — a very different matter. 



f The embryological data, to which Darwin attached great importance, 

 admit of a phylogenetic interpretation which supports the view that the 

 presence of frontal weapons in both sexes was a primitive character. 



u2 



