158 
SEXUAL SELECTION : BIRDS. 
P ^ 1 
j {0 
not all, of the successive steps might be transfer^ ^ 
both sexes, and the female would then closely res eI f j. 
the male. There can hardly be a doubt that th ' 3 , 
the cause of the male pouter pigeon having a som e " 
larger crop, and of the male carrier pigeon having 
what larger wattles, than their respective females 
fanciers have not selected one sex more than the 0 ^ 
and have had no wish that these characters shorn 1 
more strongly displayed in the male than in the fe^ 
yet this is the case with both breeds. m 
The same process would have to be followed, a 011 .!,,! 
same difficulties would be encountered, if it were de sl 
to make a breed with the females alone of soW e 1 
colour. j|i 
Lastly, our fancier might wish to make a breed ' v V 
the two sexes differing from each other, and both 
the parent-species. Here the difficulty would ho ^ 
treme, unless the successive variations were fro ' 11 J 
first sexually limited on both sides, and then there 
be no difficulty. We see this with the fowl; tiff 8 ( jy 
two sexes of the pencilled Hamburghs differ g^^ r j- 
from each other, and from the two sexes of the 9 
ginal Gallus lankiva ; and both are now kept c° iv ^i. 
to their standard of excellence by continued sek 1(t „ 
which would be impossible unless the distinctive oh ^ 
ters ol both wore limited in their transmission. ^ 
Spanish fowl offers a more curious case ; the und 1 , ji; , 
an immense comb, but some of the successive vari^Vy 
by the accumulation of which it was acquired, ; 
to have been transferred to the female ; for she h?^ 
comb many times larger than that of the females ot j,) 
parent-species. But the comb of the female diff ef# j ( ,ji 
one respect from that of the male, for it is apt 
over; and within a recent period it has been 
to 
off 
de 1 " 
by the fancy that this should always be the case > 1 
