The Descent of Man

in the English Carrier pigeon, and the crop in
the Pouter, are more highly developed in the
male than in the female; and although these
characters have been gained through longcontinued
selection by man, the slight differences
between the sexes are wholly due to the
form of inheritance which has prevailed; for
they have arisen, not from, but rather in opposition
to, the wish 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 sex alone, and some to both
sexes, we find in the different breeds of the same
species all gradations between great sexual
dissimilarity and complete similarity. Instances
have already been given with the breeds of the
fowl and pigeon, and under nature analogous
cases are common. With animals under domestication,
but whether in nature I will not ventu-