I have begun my discussion on sexual
selection by showing that new characters often appear in one sex and are
transmitted to that sex alone, and that from some unknown cause such
characters apparently appear oftener in the male than in the female.
Secondly, characters may be developed and be confined to the male, and
long afterwards be transferred to the female. Thirdly, characters may,
again, arise in either sex and be transmitted to both sexes, either in
an equal or unequal degree. In this latter case I have supposed that the
survival of the fittest has come into play with female birds and kept
the female dull-coloured. With respect to the absence of spurs in female
gallinaceous birds, I presume that they would be in the way during
incubation; at least, I have got the case of a German breed of fowls in
which the hens were spurred, and were found to disturb and break their
eggs much.
With respect to the females of deer not having horns, I presume it is to
save the loss of organised matter.
In your note you speak of sexual selection and protection as sufficient
to account for the colouring of all animals; but it seems to me doubtful
how far this will come into play with some of the lower animals, such as
sea anemones, some corals, etc.
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