88 SEXUAL DIMORPHISM 



antlers were mature, that is, after the velvet had been shed, 

 or was ready to be shed, the antlers always dropped oft' 

 within thirty days afterwards, however distant might be the 

 time at which they would have been shed in the entire stag. 

 In the following summer the antlers develop again, as in the 

 entire stag, but with important differences. In the first 

 place, if the castrated stag is young, having only a spike 

 antler, the new antler will be a spike of nearly the same 

 length, no more advanced stage will be reached, as in the 

 entire stag, but the same stage is repeated. Secondly, the 

 new antlers never lose their velvet. In the winter the ab- 

 normal antlers may be frozen and broken off nearly down to 

 the burr, but not below the burr, or they may be carried 

 through the winter, only a few points being broken. In the 

 following summer irregular growths take place on the old 

 antler, covered with its persistent velvet. These growths 

 usually take the form of large irregular tubercles. As in 

 winter, projections are continually broken off, and in summer 

 more tubercles grow, a very irregular antler is the result, and 

 on the whole more loss takes place than growth, so that the 

 whole mass gets smaller. These experiments were made on 

 the wapiti, the Canadian deer, which is very similar to the 

 European red deer. The results agree very closely with those 

 described by Dr. Fowler from experiments which have been 

 made on fallow-deer. There is this addition, however, to be 

 made from Dr. Fowler's paper ; that when castration is per- 

 formed at birth, little processes are developed two to four inches 

 in length, covered with skin. It will be seen, therefore, that 

 castration does not entirely prevent the development of 

 antlers, but it does entirely prevent the normal peeling of 

 the velvet and normal shedding of the antler developed after 

 castration. This strongly supports the theory that the peel- 

 ing of the velvet, and consequent shedding of the antler, 

 were originally due to mechanical irritations associated with 



