SEXUAL SELECTION 673 



Mr. Wallace,' who believes that in almost all cases the suc- 

 cessive variations tended at first to be transmitted equally 

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

 natural selection, from acquiring the conspicuous colors 

 of the male, owing to the danger which she would thus 

 have inctirred 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 subse- 

 quently limited in its transmission to one sex alone by 

 means of natural selection. We must bear in mind, as 

 shown in the preliminary chapter on sexual selection, 

 that characters which are limited in their development to 

 one sex are always latent in the other. An imaginary illus- 

 tration 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 colored of a 

 pale blue, while the females retained their former slaty 

 tint. As with pigeons characters of all kinds are usually 

 transmitted to both sexes equally, the fancier would have 

 to try to convert this latter form of inheritance into sexu- 

 ally 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 re- 

 curred, would be to make his whole stock of a lighter 

 blue. But our fancier would be compelled to match, gen- 

 eration after generation, his pale-blue males with slaty 

 females, for he wishes to keep the latter of this color. 

 The result would generally be the production either of a 

 mongrel piebald lot, or more probably the speedy and com- 

 plete loss of the pale-blue tint; for the primordial slaty 

 color would be transmitted with prepotent force. Suppos- 

 ing, however, that some pale blue males and slaty females 



* "WeetminBter Bevlew." Jnly. 1867. "Journal of VtmA," voL L, 1868!, 

 p. 18 



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