SEXUAL SELECTION 277 



and the same sex. So again tiie primary sexual organs, 

 and those for nourishing or protecting the young, come 

 under the same influence; for those individuals which gen- 

 erated or nourished their offspring best would leave, cceteria 

 paribus, the greatest number to inherit their superiority, 

 while those which generated or nourished their offspring 

 badly would leave but few to inherit their weaker powers. 

 As the male has to find the female, he requires 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. Wallace informs 

 me that the males of certain moths cannot unite with the 

 females if their tarsi or feet are broken. The males of many 

 oceanic crustaceans, when adult, have their legs and antennae 

 modified in an extraordinary manner for the prehension of 

 the female; hence we may suspect that it is because these 

 animals are washed about by the waves of the open sea that 

 they require these organs in order to propagate their kind, 

 and if so, their development has been the result of ordinary 

 or natural selection. Some animals extremely low in the 

 Bcale have been modified for this same purpose; thus 

 the males of certain parasitic worms, when fully grown, 

 have the lower surface of the terminal part of their bodies 

 roughened like a rasp, and with this they coil round and 

 permanently hold the females.* 



When the two sexes follow exactly the same habits of 

 life, and the male has the sensory or locomotive organs more 



* M. Perrier advances this caee ("Bevue Sdentiflque," Feb. 1, 1873, 

 p. 865) as one fatal to the belief in sexual selection, inasmuch as he supposes 

 that I attribute all the differences between the sexes to sexual selection. This 

 distinguished naturalist, therefore, h'ke so many other Frenchmen, has not 

 taken the trouble to understand even the first principles of sexual selection. 

 An English naturalist insists that the claspers of certain male animals could 

 not have been developed through the choice of the female! Had I not met 

 with this remark, I should not have thought it possible for any one to have 

 lead this chapter and to have imagined that I maintain that the choice of the 

 female had anything to do with the development of the prehensile organs in 

 the male. 



