The Descent of Man

cases to be merely ornamental, though they
sometimes serve as a defence against rival males.
There is even reason to suspect that the
branching horns of stags, and the elegant horns
of certain antelopes, though properly serving as
weapons of offence or defence, have been partly
modified for ornament.
When the male differs in colour from the female,
he generally exhibits darker and more strongly-contrasted
tints. We do not in this class
meet with the splendid red, blue, yellow, and
green tints, so common with male birds and
many other animals. The naked parts, however,
of certain Quadrumana must be excepted; for
such parts, often oddly situated, are brilliantly
coloured in some species. The colours of the
male in other cases may be due to simple variation,
without the aid of selection. But when the
colours are diversified and strongly pronounced,
when they are not developed until near
maturity, and when they are lost after emascu-