MAMMALS 83 



From the above considerations it seems to me there 

 are two possible views concerning the evolution of the 

 antlers in the Cervidae. The first is as follows. We may 

 suppose that the young stags fought with their heads, and as 

 a result of this, inflammation of the periosteum was caused. 

 This inflammation caused a process of hypertrophic ossification 

 or exostosis. We may suppose that as the inflammation ceased, 

 and the ossification was completed, the stag felt an irritation 

 in the previously inflamed skin, and rubbed it violently 

 against trees, laying the new bone bare. The ossification 

 went on longer and more rapidly at the base of the projection, 

 where the laceration of the skin caused more inflammation, 

 and so gave rise to the burr. Then, when this also had run 

 its course, the exostosis was shed naturally in consequence 

 of the absorption of the dead bone by the living blood- 

 vessels at the base. We may suppose all this to have 

 happened within a year, the process being repeated da capo 

 at the next rutting season. According to this hypothesis the 

 loss of the velvet and consequent death and shedding of the 

 antler is due not to fighting, but to a spontaneous effort 

 on the part of the stag, and this is due to an irritation 

 caused by the acute and inflammatory character of the 

 process by which the exostosis was formed. In this 

 respect the hypothesis agrees with that which occurs in 

 the existing stag, but it does not agree with the fact that 

 in the latter the antler develops before fighting commences, 

 and that during its development the velvet appears to be so 

 sensitive that any contact is painful. On this hypothesis, 

 therefore, we must assume that when the process of hyper- 

 trophy became hereditary, it was so hastened as to follow 

 soon after the shedding of the old antler, instead of following 

 the irritation of the fighting period. 



Objections to this hypothesis arise also from the possibility 

 mentioned above, that the regular shedding of the antlers 



