The Descent of Man

progenitor, and now preserved by the young
alone. In all such cases the old have had their
colours changed in the course of time, whilst
the young have remained but little altered, and
this has been effected through the principle of
inheritance at corresponding ages.
This same principle applies to many birds belonging
to various groups, in which the young
closely resemble each other, and differ much
from their respective adult parents. The young
of almost all the Gallinaceae, and of some distantly
allied birds such as ostriches, are covered
with longitudinally striped down; but this character
points back to a state of things so remote
that it hardly concerns us. Young cross-bills
(Loxia) have at first straight beaks like those of
other finches, and in their immature striated
plumage they resemble the mature red-pole
and female siskin, as well as the young of the
goldfinch, greenfinch, and some other allied
species. The young of many kinds of buntings