216 Heredity. 



males. ... Of the males the strongest, and, with some 

 species, the best armed, drive away the weaker males; 

 and the former would then unite with the more vigor- 

 ous and best nourished females, as these are the first to 

 breed. Such vigorous pairs would surely rear a larger 

 number of offspring than the retarded females, which 

 would be compelled to unite with the conquered and 

 less powerful males; and this is all that is wanted to 

 add, in the course of successive generations, to the size, 

 strength, and courage of the males, or to improve their 

 weapons. But in a multitude of cases the males which 

 conquer other males do not obtain possession of the fe- 

 males independently of choice on the part of the latter. 

 The courtship of animals is by no means so simple and 

 short an affair as might be thought. The females are 

 most excited by, or prefer pairing with, the more orna- 

 mented males, or those which are the best songsters, or 

 play the best antics; but it is obviously probable, as has 

 been actually observed in some cases, that they would 

 at the same time prefer the most vigorous and lively 

 males. . . . And this apparently has sufficed during a 

 long course of generations to add not only to the strength 

 and fighting power of the males, but likewise to their 

 various ornaments or other attractions. . . . To sum up 

 on the means through which, so far as we can judge, 

 sexual selection has led to the development of secondary 

 sexual characters : It has been shown that the largest 

 number of vigorous offspring will be reared from the 

 pairing of the strongest and best armed males, which 

 have conquered other males, with the most vigorous and 

 best-nourished females, which are the first to breed in 

 the spring. Such females, if they select the most at- 

 tractive and, at the same time, vigorous males, will rear 

 a larger number of offspring than the retarded females, 



