The Descent of Man

e to say, one sex may lose characters proper to
it, and may thus come somewhat to resemble
the opposite sex; for instance, the males of some
breeds of the fowl have lost their masculine
tail-plumes and hackles. On the other hand, the
differences between the sexes may be increased
under domestication, as with merino sheep, in
which the ewes have lost their horns. Again,
characters proper to one sex may suddenly appear
in the other sex; as in those sub-breeds of
the fowl in which the hens acquire spurs whilst
young; or, as in certain Polish sub-breeds, in
which the females, as there is reason to believe,
originally acquired a crest, and subsequently
transferred it to the males. All these cases are
intelligible on the hypothesis of pangenesis; for
they depend on the gemmules of certain parts,
although present in both sexes, becoming,
through the influence of domestication, either
dormant or developed in either sex.