228 THE DESCENT OF MAN. 



cases the variations, through the accumulation of which the male 

 acquired his proper masculine characters, must have occurred at a 

 somewhat late period of life; otherwise the young males would 

 have been similarly characterized; and comformalily with our rule, 

 the variations are transmitted to and developed in the adult males 

 alone. When, on the other hand, the adult male closely resembles 

 the young of both sexes (these, with rare exceptions, being alike), 

 he generally resembles the adult female; and in most of these cases 

 the variations through which the young and old acquired their 

 present characters, probably occurred, according to our rule, dur- 

 ing youth. But there is here room for doubt, for characters are 

 sometimes transferred to the offspring at an earlier age than that 

 at which they first appeared in the parents, so that the parents 

 may have varied when adult, and have transferred their characters 

 to their offspring whilst young. There are, moreover, many ani- 

 mals, in which the two sexes closely resemble each other, and yet 

 both differ from their young; and here the characters of the adults 

 must have been acquired late in life; nevertheless, these char- 

 acters, in apparent contradiction to our rule, are transferred to 

 both sexes. We must not, however, overlook the possibility or 

 even probability of successive variations of the same nature occur- 

 ring, under exposure to similar conditions, simultaneously in both 

 sexes at a rather late period of life; and in this case the variations 

 would be transferred to the offspring of both sexes at a corre- 

 sponding late age; and there 'vould then be no real contradiction 

 to the rule that variations occurring late in life are transferred 

 exclusively to the sex in which they first appeared. This latter 

 rule seen)s to hold true more generally than the second one, 

 namely, that variations which occur in either sex early in life tend 

 to be transferred to both sexes. As it was obviously impossible 

 even to estimate in how large a number of cases throughout the 

 animal kingdom these two propositions held good, it occurred to 

 me to investigate some striking or crucial instances, and to rely 

 on the result. 



An excellent case for investigation is afforded by the Deer 

 family. In all the species, but one, the horns are developed only 

 in the males, though certainly transmitted through the females, 

 and capable of abnormal development in them. In the reindeer, 

 on the other hand, the female is provided with horns; so that in 

 this species, the horns ought, according to our rule, to appear early 

 in life, long before the two sexes are mature and have come to dif- 

 fer much in constitution. In all the other species the horns ought 

 to appear later in life, which would lead to their development in 

 that sex alone, in which they first appeared in the progenitor of 

 the vhole Family. Now in seven species, belonging to distinct 

 Sections of the family and inhabiting different regions, in which 

 the stags alone bear horns, I find that the horns first appear at 



