Chap. XV. SEXUALLY-LIMITED INHERITANCE. 155 



has been discussed in some very interesting papers by 

 Mr. Wallace,^ who beheves that in almost all cases the 

 successive variations tended at first to be transmitted 

 equally to both sexes ; but that the female was saved, 

 through natural selection, from acquiring the conspicu- 

 ous colours of the male, owing to the danger which she 

 would thus have incurred during incubation. 



This view necessitates a tedious discussion on a 

 difficult point, namely whether the transmission of a 

 character, which is at first inherited by both sexes, can 

 be subsequently limited in its transmission, by means 

 of selection, to one sex alone. We must bear in mind, 

 as shewn in the preliminary chapter on sexual selec- 

 tion, that characters which are limited in their de- 

 velopment to one sex are always latent in the other. 

 An imaginary illustration will best aid us in seeing 

 the difficulty of the case : we may suppose that a 

 fancier wished to make a breed of pigeons, in which 

 the males alone should be coloured of a pale blue, 

 whilst the females retained their former slaty tint. As 

 with pigeons characters of all kinds are usually trans- 

 mitted to both sexes equally, the fancier would have 

 to try to convert this latter form of inheritance into 

 sexually-limited transmission. All that he could do 

 would be to persevere in selecting every male pigeon 

 which was in the least degree of a paler blue ; and the 

 natural result of this process, if steadily carried on for 

 a long time, and if the pale variations were strongly 

 inherited or often recurred, would be to make his whole 

 stock of a lighter blue. But our fancier ^^ ould be com- 

 pelled to match, generation after generation, his ]pa\e 

 blue males with slaty females, for he wishes to keep the 



- 'Westminster Review,' July, 1867. 'Journal of Travel,' vol. i. 

 1868, p. 73. 



