SEXUAL SELECTION 313 



Other hand, the tortoise-shell color, which is confined to 

 female cats, is quite distinct at birth, and this case violates 

 the rule. There is a breed of pigeons in which the males 

 alone are streaked with black, and the streaks can be de- 

 tected even in the nestlings; but they become more con- 

 spicuous at each successive moult, so that this case partly 

 opposes and partly supports the rule. With the English 

 Carrier and Pouter pigeons, the fijU development of the 

 wattle and the crop occurs rather late in life, and, conform- 

 ably with the rule, these characters are transmitted in full 

 perfection to the males alone. The following cases perhaps 

 come within the class previously alluded to, in which both 

 sexes have varied in the same manner at a rather late 

 period of life, and have consequently transferred their new 

 characters to both sexes at a corresponding late period; 

 and if so, these cases are not opposed to our rule: There 

 exist sub-breeds of the pigeon, described by Neumeister, " 

 in which both sexes change their color during two or three 

 moults (as is likewise the case with the Almond Tumbler) ; 

 nevertheless, these changes, though occurring rather late in 

 life, are common to both sexes. One variety of the Canary- 

 bird, namely, the London Prize, offers a nearly analogous 

 case. 



"With the breeds of the Fowl, the inheritance of vari- 

 ous characters by one or both sexes seems generally deter- 

 mined by the period at which such characters are developed. 

 Thus in all the many breeds in which the adult male differs 

 greatly in color from the female, as well as from the wild 

 parent- species, he differs also from the young male, so that 

 the newly acquired characters must have appeared at a 

 rather late period of life. On the other hand, in most of 

 the breeds in which the two sexes resemble each other, the 

 young are colored in nearly the same manner as their 

 parents, and this renders it probable that their colors first 

 appeared early in life. We have instances of this fact in 



*" "Das Ganze der Taubenzuclit, " 1837, s. 21, 24. For the caae of the 

 , streaked pigeons, see Dr. Ohapuis, "Le pigeon voyageur Beige, " 1865, p. 81. 

 Descent — Vol. I. — 14 



