ced.

It is to this form of male rivalry that Mr. Darwin first applied the
term "sexual selection." It is evidently a real power in nature; and to
it we must impute the development of the exceptional strength, size, and
activity of the male, together with the possession of special offensive
and defensive weapons, and of all other characters which arise from the
development of these or are correlated with them. But he has extended
the principle into a totally different field of action, which has none
of that character of constancy and of inevitable result that attaches to
natural selection, including male rivalry; for by far the larger portion
of the phenomena, which he endeavours to explain by the direct action of
sexual selection, can only be so explained on the hypothesis that the
immediate agency is female choice or preference. It is to this that he
imputes the origin of all secondary sexual characters other than weapons
of offence and defence, of all the ornamental crests and accessory
plumes of birds, the stridulating sounds of insects, the crests and
beards of monkeys and other mammals, and the brilliant colours and
patterns of male birds and butterflies. He even goes further, and
imputes to it a large portion of the brilliant colour that occurs in
both sexes, on the principle that variations occurring in one sex are
sometimes transmitted to the same sex only, sometimes to both, owing to
peculiarities in the laws of inheritance. In this extension of sexual
selection to include the action of female choice or preference, and in
the attempt to give to that choice such wide-reaching effects, I am
unable to follow him more than a very little way; and I will now state
some of the reasons why I think his views are unsound.

_Sexual Characters due to Natural Selection._

Besides the acquisition of weapons by the male for the purpose of
fighting with other males, there are some other sexual characters which
may have been produced by natural selection. Such are the various sounds
and odours which are peculiar to the male, and which serve as a call to
the female or as an indication of his presence. These are evidently a
valuable addition to the means of recognition of the two sexes, and are
a further indication that the pairing season has arrived; and the
production, intensification, and differentiation of these sounds and
odours are clearly within the power of natural selection. The same
remark will apply to the peculia