III PROTECTIVE RESEMBLANCES AMONG ANIMALS 89 
the colours of the vegetable as compared with the wonderful 
diversity of the animal world. There appears no good reason 
why trees and shrubs should not have been adorned with as 
many varied hues and as strikingly designed patterns as birds 
and butterflies, since the gay colours of flowers show that 
there is no incapacity in vegetable tissues to exhibit them. 
But even flowers themselves present us with none of those 
wonderful designs, those complicated arrangements of stripes 
and dots and patches of colour, that harmonious blending of 
hues in lines and bands and shaded spots, which are so 
general a feature in insects. It is the opinion of Mr. Darwin 
that we owe much of the beauty of flowers to the necessity 
of attracting insects to aid in their fertilisation, and that 
much of the development of colour in the animal world is 
due to “sexual selection,” colour being universally attractive, 
and thus leading to its propagation and increase ; but while 
fully admitting this, it will be evident, from the facts and 
arguments here brought forward, that very much of the 
variety both of colour and markings among animals is due to 
the supreme importance of concealment, and thus the various 
tints of minerals and vegetables have been directly repro- 
duced in the animal kingdom, and again and again modified 
as more special protection became necessary. We shall thus 
have two causes for the development of colour in the animal 
world, and shall be better enabled to understand how, by 
their combined and separate action, the immense variety we 
now behold has been produced. Both causes, however, will 
come under the general law of “Utility,” the advocacy of 
which, in its broadest sense, we owe almost entirely to Mr. 
Darwin. A more accurate knowledge of the varied pheno- 
mena connected with this subject may not improbably give 
us some information both as to the senses and the mental 
faculties of the lower animals. For it is evident that if 
colours which please us also attract them, and if the various 
disguises which have been here enumerated are equally 
deceptive to them as to ourselves, then both their powers of 
vision and their faculties of perception and emotion must be 
essentially of the same nature as our own—a fact of high 
philosophical importance in the study of our own nature and 
our true relations to the lower animals, 
