bable
that the primitive colours of all animals were so. During the long
course of animal development other modes of protection than concealment
by harmony of colour arose, and thenceforth the normal development of
colour due to the complex chemical and structural changes ever going on
in the organism, had full play; and the colours thus produced were again
and again modified by natural selection for purposes of warning,
recognition, mimicry, or special protection, as has been already fully
explained in the preceding chapters.

Mr. Taylor has, however, called attention to an important principle
which underlies the various patterns or ornamental markings of
animals--namely, that diversified coloration follows the chief lines of
structure, and changes at points, such as the joints, where function
changes. He says, "If we take highly decorated species--that is, animals
marked by alternate dark or light bands or spots, such as the zebra,
some deer, or the carnivora, we find, first, that the region of the
spinal column is marked by a dark stripe; secondly, that the regions of
the appendages, or limbs, are differently marked; thirdly, that the
flanks are striped or spotted, along or between the regions of the lines
of the ribs; fourthly, that the shoulder and hip regions are marked by
curved lines; fifthly, that the pattern changes, and the direction of
the lines, or spots, at the head, neck, and every joint of the limbs;
and lastly, that the tips of the ears, nose, tail, and feet, and the eye
are emphasised in colour. In spotted animals the greatest length of the
spot is generally in the direction of the largest development of the
skeleton."

This structural decoration is well seen in many insects. In
caterpillars, similar spots and markings are repeated in each segment,
except where modified for some form of protection. In butterflies, the
spots and bands usually have reference to the form of the wing and the
arrangement of the nervures; and there is much evidence to show that the
primitive markings are always spots in the cells, or between the
nervures, or at the junctions of nervures, the extension and coalescence
of these spots forming borders, bands, or blotches, which have become
modified in infinitely varied ways for protection, warning, or
recognition. Even in birds, the distribution of colours and markings
follows generally the same law. The crown of the head, the throat, the
ear-coverts, and the eyes have usually