TJie Evidence from Sexual Characters. 213 



teily skill. The attempt to point out within the 

 limits of a single chapter the errors of his conclusion is 

 beset with many difficnlties, and I shall be compelled to 

 treat the subject with brevity, and to leave unsaid much 

 which might be urged did space permit. 



As an introduction to the discussion of the subject, I 

 shall quote Darwin's statement of the meaning of the 

 term ''sexual selection." He says: "This depends on 

 the advantage which ceitain individuals have over other 

 individuals of the same sex and species in exclusive re- 

 lation to reproduction. When the two sexes differ in 

 structure in relation todifferent habits of life, they have, 

 no doubt, been modified through natural selection, ac- 

 companied by inheritance limited to one and the same 

 sex. So, again, the primary sexual organs, and those 

 for nourishing and protecting the young, come under 

 the same head; for those individuals Avhich generated 

 or nourished their offspring best, would leave, cceieris 

 paribus, the greatest number to inherit their superi- 

 ority; Avhile those which generated or nourished their 

 offspring badly, would leave but few to inherit their 

 weaker jiowers. As the male has to search for the fe- 

 male, he requires for this purpose organs of sense and 

 locomotion, but if these organs are necessary for the 

 other purposes of life, as is generally the case, they will 

 have been developed through natural selection. When 

 the male has found the female he sometimes absolutely 

 requires prehensile organs to hold her; thus Dr. Wal- 

 lace informs me that the males of certain moths 

 cannot unite with the females if their tarsi or feet are 

 broken. . . . W^hen the two sexes follow exactly the 

 same habits of life, and the male has more highly devel- 

 oped sense organs or locomotive organs than the female, 

 it may be that these in their perfect state are indispen- 



