[24]
[Illustration: FIG. 15.--Variation of 8 skulls (Ursus labiatus).]
[Illustration: FIG. 16.]
The few facts now given, as to variations of the internal parts of
animals, might be multiplied indefinitely by a search through the
voluminous writings of comparative anatomists. But the evidence already
adduced, taken in conjunction with the much fuller evidence of variation
in all external organs, leads us to the conclusion that wherever
variations are looked for among a considerable number of individuals of
the more common species they are sure to be found; that they are
everywhere of considerable amount, often reaching 20 per cent of the
size of the part implicated; and that they are to a great extent
independent of each other, and thus afford almost any combination of
variations that may be needed.
It must be particularly noticed that the whole series of
variation-diagrams here given (except the three which illustrate the
number of varying individuals) in every case represent the actual amount
of the variation, not on any reduced or enlarged scale, but as it were
life-size.
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