250 BEACH GRASS 



to please the female more than its rivals please 

 the same bird appeals to us as a very reasonable 

 and very human point of view. This is what 

 leads to courtship, and in this courtship rivalry 

 it is natural to suppose that the best bird wins. 

 Although it has been somewhat the fashion of 

 late to decry Darwin's theory of sexual selec- 

 tion and to substitute others for it, its simplic- 

 ity and common sense still appeal to many, 

 and it is worth while occasionally to consult the 

 original text. 



Darwin published his ''Origin or Species" in 

 1859. In Chapter IV he says he is led "to say a 

 few words on what I have called Sexual Selec- 

 tion. This form of selection depends, not on a 

 struggle for existence in relation to other organic 

 beings or to external conditions, but on a struggle 

 between the individuals of one sex, generally the 

 males, for the possession of the other sex. The 

 result is not death to the unsuccessful competitor, 

 but few or no offspring. Sexual selection is, 

 therefore, less rigorous than natural selection. 

 Generally, the most vigorous males, those which 

 are best fitted for their places in nature, will 



