BIRDS— SEXUALLY LIMITED INHERITANCE. 441 



followed with success by Mr. Bsquilant in the case of silver tur- 

 bits. 



With fowls, variations of color, limited in their transmission 

 to the male sex, habitually occur. When this form of inheritance 

 prevails, it might well jiappen that some of the successive varia- 

 tions would be transferred to the female, who would then slightly 

 resemble the male, as actually occurs in some breeds. Or again, 

 the greater number, but not all, of the successive steps might be 

 transferred to both sexes, and the female would then closely re- 

 semble the male. There can hardly be a doubt that this is the 

 cause of the male pouter pigeon having a somewhat larger crop, 

 and of the male carrier pigeon having somewhat larger wattles, 

 than their respective females; for fanciers have not selected 

 one sex more than the other, and have had no wish that these 

 characters should be more strongly displayed in the male than 

 in the female, yet this is the case with both breeds. 



The same process would have to be followed, and the same 

 difficulties encountered, if it were desired to make a breed with 

 the females alone of some new color. 



Lastly, our fancier might wish to make a breed with the two 

 sexes differing from each other, and both from the parent-species. 

 Here the difficulty would be extreme, unless the successive varia- 

 tions were from the first sexually limited on both sides, and 

 then there would be no difficulty. We see this with the fowl; 

 thus the two sexes of the penciled Hamburghs differ greatly 

 from each other, and from the two sexes of the aboriginal Gallus 

 bankiva; and both are now kept constant to their standard of 

 excellence by continued selection, which would be impossible un- 

 less the distinctive characters of both were limited in their trans- 

 mission. The Spanish fowl offers a more curious case; the male 

 has an immense comb, but some of the successive variations, by 

 the accumulation of which it was acquired, appear to have been 

 transferred to the female; for she has a comb many times larger 

 than that of the females of the parent-species. But the comb of 

 the female differs in one respect from that of the male, for it is 

 apt to lop over; and within a recent period it has been ordered 

 by the fancy that this should always be the case, and success has 

 quickly followed the order. Now the lopping of the comb must 

 be sexually limited in its transmission, otherwise it would pre- 

 vent the comb of the male from being perfectly upright, which 

 would be abhorrent to every fancier. On the other hand, the up- 

 rightness of the comb in the male must likewise be a sexually- 

 limited character, otherwise it would prevent the comb of the fe- 

 male from lopping over. 



Prom the foregoing illustrations, we see that even with almost 

 unlimited time at command, it would be an extremely difficult 



