HOEN-STRUCTUEES IN THE UNGULATA. 133 



while iu the deer the antlers are shed and reproduced of 

 a larger size every year ; again, that in bullocks and 

 antelopes the females as well as the males are generally 

 furnished with them, while in most of the deer tribe, 

 except the reindeer, they are possessed by the males only. 



These two characteristics of the deer tribe seem to in- 

 dicate that in most of them the horns are not so much 

 required for the defence of the animals against external 

 enemies as to enable the strongest males to get the mastery 

 of the rest, and thus, in Darwinian language, to provide for 

 the " survival of the fittest " in the perpetuation of the 

 race. The antler, then, as a finished w^eapon, exists only 

 for a limited period of the year, and all through the time 

 of its rapid growth it is unfit to be used as a weapon, being 

 during that time covered by tender hairy skin, which 

 would bleed if roughly struck. 



This periodical difference during the time of growth on 

 the one hand and of use as a weapon on the other is 

 associated also with differences of temper and of courage 

 in the stag, the ordinary timidity during growth being 

 replaced by quarrelsomeness and boldness when the fight- 

 ing organ is complete and when its previously tender skin 

 has died, shrivelled, and begun to peel off. It could 

 scarcely then be expected that with such differences in the 

 rapidity of growth, the structure of the horns should be 

 identical in the deer and the antelope. We have seen 

 above that Owen spoke of the two systems to which the two 

 kinds of horn especially belong, and which I may call, 

 shortly, the skin structure and the bone structure, and in 

 the case of the deer he refers it to the bony system only. 

 But in truth all horns belong to both systems, for in the 

 deer we see both skin and bone developed during the 

 growth of the antler, and it is only when it is completed as 



