adult, have their legs and antennae modified in an extraordinary manner
for the prehension of the female; hence we may suspect that it is
because these animals are washed about by the waves of the open sea,
that they require these organs in order to propagate their kind, and if
so, their development has been the result of ordinary or natural
selection. Some animals extremely low in the scale have been modified
for this same purpose; thus the males of certain parasitic worms, when
fully grown, have the lower surface of the terminal part of their
bodies roughened like a rasp, and with this they coil round and
permanently hold the females. (4. M. Perrier advances this case ( Revue
Scientifique, Feb. 1, 1873, p. 865) as one fatal to the belief in
sexual election, inasmuch as he supposes that I attribute all the
differences between the sexes to sexual selection. This distinguished
naturalist, therefore, like so many other Frenchmen, has not taken the
trouble to understand even the first principles of sexual selection. An
English naturalist insists that the claspers of certain male animals
could not have been developed through the choice of the female! Had I
not met with this remark, I should not have thought it possible for any
one to have read this chapter and to have imagined that I maintain that
the choice of the female had anything to do with the development of the
prehensile organs in the male.)
When the two sexes follow exactly the same habits of life, and the male
has the sensory or locomotive organs more highly developed than those
of the female, it may be that the perfection of these is indispensable
to the male for finding the female; but in the vast majority of cases,
they serve only to give one male an advantage over another, for with
sufficient time, the less well-endowed males would succeed in pairing
with the females; and judging from the structure of the female, they
would be in all other respects equally well adapted for their ordinary
habits of life. Since in such cases the males have acquired their
present structure, not from being better fitted to survive in the
struggle for existence, but from having gained an advantage over other
males, and from having transmitted this advantage to their male
offspring alone, sexual selection must here have come into action. It
was the importance of this distinction which led me to designate this
form of selection as Sexual Selection. So again, if the chief service
rendered to the male by his prehensile organs is to prevent the escape
of the female before the arrival of other males, or when assaulted by
them, these organs will have been perfected through sexual selection,
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