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The Descent of Man

The Descent of Man

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Frequently in the same group <strong>of</strong> birds, even<br />

within the same genus, for instance in an Australian<br />

genus <strong>of</strong> parrakeets (Platycercus), the<br />

young <strong>of</strong> some species closely resemble, whilst<br />

the young <strong>of</strong> other species differ considerably,<br />

from their parents <strong>of</strong> both sexes, which are alike.<br />

(28. Gould, ibid. vol. ii. pp. 37, 46, 56.) Both<br />

sexes and the young <strong>of</strong> the common jay are<br />

closely similar; but in the Canada jay (Perisoreus<br />

canadensis) the young differ so much from<br />

their parents that they were formerly described<br />

as distinct species. (29. Audubon, 'Ornith. Biography,'<br />

vol. ii. p. 55.)<br />

I may remark before proceeding that, under the<br />

present and next two classes <strong>of</strong> cases, the facts<br />

are so complex and the conclusions so doubtful,<br />

that any one who feels no especial interest<br />

in the subject had better pass them over.<br />

<strong>The</strong> brilliant or conspicuous colours which characterise<br />

many birds in the present class, can<br />

rarely or never be <strong>of</strong> service to them as a pro-

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