Chap. VIII. 
SEXUAL SELECTION. 
283 
tion ; but a few instances may here be given. There 
are breeds of the sheep and goat, in which the horns 
°f the male differ greatly in shape from those of the 
female; and these "differences, acquired under domes- 
tication, are regularly transmitted to the same sex. 
With tortoise-shell cats the females alone, as a general 
rule, are thus coloured, the males being rusty-red. 
With most breeds of the fowl, the characters proper 
to each sex are transmitted to the same sex alone, feo 
general is this form of transmission that it is an ano- 
maly when we see in certain breeds variations trans- 
mitted equally to both sexes. There are also certain 
s ub-breeds of” the fowl in which the males can hardly 
ho distinguished from each other, whilst the females 
differ considerably in colour. With the pigeon the 
sexes of the parent-species do not differ in any external 
character; nevertheless in certain domesticated breeds 
We male is differently coloured from the female . 22 
The wattle in the English Carrier pigeon and the crop 
in the Pouter are more highly developed in the male 
Wan in the female; and although these characters have 
been gained through long-continued selection by man, 
We difference between the two sexes is wholly due to 
die form of inheritance which lias prevailed; for it 
has arisen, not from, hut rather in opposition to, the 
wishes of the breeder. , 
Most of our domestic races have been formed by the 
accumulation of many slight variations ; and as some 
of the successive steps have been transmitted to one 
alone, and some to both sexes, we find m the diffe- 
I'ent breeds of the same species all gradations between 
gloat sexual dissimilarity and complete similarity. In- 
22 Dr. Cliapuis, ‘Le Pigeon Voyagcnr Beige,’ 1865, p. 87. Boitard 
Corbie, ‘Les Pigeons de Voliere/ &c., 1824, p. 1/3. 
