102 SEXUAL DIMORPHISM 



the bucks run for about six weeks, and during this period 

 fight with great courage and even a degree of ferocity. . . . 

 Both parties run at each other with their heads lowered and 

 their eyes flashing angrily, and while they strike with their 

 horns they wheel and bound with prodigious activity and 

 rapidity, giving and receiving severe wounds, sometimes, like 

 fencers, getting within each other's points and each hooking 

 his antagonist with the recurved branches of his horns, which 

 bend considerably inward and downward." Caton states 

 that in old bucks the horn is shed in October, and the new 

 growth is not completed till July or August, so that the 

 lighting is limited to the rutting season. 



Comparison of these facts with the very brief paragraph 

 in Moller's Chirurgie fur Thierdrzte concerning the shedding 

 of horns in the ox, is sufficient to show the close similarity of 

 the processes in the two cases. Moller merely states that 

 loosening of one or both horns in cattle occurs under the 

 same circumstances as fracture of the horn core, that is to 

 say, from violent pushing or striking with the horn, from 

 mechanical pressure and impact. The old horn-sheath may 

 be merely loosened or entirely separated. The horn may be 

 completely regenerated, but the new horn is never perfect 

 in size and shape. The latter fact may to some appear 

 inconsistent with my conclusions, but I think it is obvious 

 at any rate that if irritation and renewal were frequent 

 the growth of the epidermis might be stimulated so as to 

 produce a new horn rather larger than its predecessor or as 

 large. 



It must be observed that the prong-buck differs from 

 ordinary antelopes in the limitation and corresponding 

 intensity of its sexual activity, and this would be the 

 natural result of the succession of seasons. The prong- 

 buck is confined to the temperate region of the western 

 part of North America. Scarcity of food and cold would 





