314 
SEXUAL selection: mammals. 
Paet IL 
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 emasculation, we can hardly avoid the conclusion 
that they have been acquired through sexual selection for 
the sake of ornament, and have been transmitted exclu- 
sively, or almost exclusively, to the same sex. When 
both sexes are coloured in the same manner, and the 
colours are conspicuous or curiously arranged, without 
being of the least apparent use as a protection, and 
especially when they are associated wnth various other 
ornamental appendages, we are led by analogy to the 
same conclusion, namely, that they have been acquired 
through sexual selection, although transmitted to both 
sexes. That conspicuous and diversified colours, whether 
confined to the males or common to both sexes, are as 
a general rule associated in the same groups and sub- 
groups with other secondary sexual characters, serving 
for war or for ornament, will be found to hold good if 
we look back to the various cases given in this and 
the last chapter. 
The law of the equal transmission of characters to 
both sexes, as far as colour and other ornaments are 
concerned, has prevailed far more extensively with 
mammals than with birds ; but in regard to weapons, 
such as horns and tusks, these have often been trans- 
mitted either exclusively, or in a much higher degree 
to the males than to the females. This is a surprising 
circumstance, for as the males generally use their 
weapons as a defence against enemies of all kinds, 
these weapons would have been of service to the fe- 
male. Their absence in this sex can be accounted for,, 
as far as we can see, only by the form of inheritance 
which has prevailed. Finally with quadrupeds the 
