File:The bird; its form and function (1906) (14775421393).jpg

Identifier: birditsformfunct01beeb (find matches)
Title: The bird; its form and function
Year: 1906 (1900s)
Authors: Beebe, William, 1877-1962
Subjects: Birds
Publisher: New York, Holt
Contributing Library: Smithsonian Libraries
Digitizing Sponsor: Smithsonian Libraries

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Fig. 9.—Tarpon-scale, .shark-tooth, and peacock-feather; showing diversity ofstructure derived from the skin alone. 1/2 natural size. spines, whalebone, beaks and feathers. Even the hornof a rhinocerus is only a solid mass of agglutinatedhairs, while as the antithesis to this may be mentionedall down and feathers: the tiniest fluff from a humming-bird to the great pinion of a condor. If we examine a newly hatched dove or sparrow,the little, ugly, sprawling creature, at first glance, seems Feathers 21 to be entirely naked; but a closer inspection showsscanty tufts of down scattered irregularly over the body.This, like the set of milk-teeth in mammals, is usefulonly for a time, and is later pushed out by the secondor true plumage. Even more numerous than the down-
Text Appearing After Image:
FiG. 10.—Brown Pelican nestlings, showing feather papillse on body and wings. About 1/4 natural size. tufts are little pimples or dots, many hundreds of whichcover certain parts of the skin. Each of these will event-ually give rise to a perfect feather—quill, vane, barbs,and all. The under layer of skin, or dermis, is very thin inbirds, much more so than in reptiles and other animals. 22 The Bird The first intimation of the appearance of a feather, orof down, is shown by a thickened group, or pimple, ofcells in this under layer of skin, which grows and pressesupward toward the outer layer—the epidermis. This isexactly the way in which the scales of fishes and reptilesbegin to form; and if, at this stage, the tiny projectionshould flatten out, the shining scale of a carp, the armor

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