. The bird; its form and function . which, before the chick hatches from the egg,fuse into the ploughshare bone. In the ostrich-like birds ^HH^H ^HHj ^H M HHwH IP ■pi ^ ■-; I^^^^^^H 1 ^^^K i^kL. f 11 s i 1 ^^^ WF \ -^Jl ^-^ m ^H V -^ fl V^ H ■ 1 JH^^I 1 ^ 1 Fig. 317.— of Bald Eagle, showing greater fusion and morespecialization than in Fig. 316. these small bones never fuse, but remain separate through-out life—a reptilian character persistent in these strangebirds (Fig .316). The ploughshare bone is seen splendidlydeveloped in such a bird of strong flight as the Bald that
. The bird; its form and function . which, before the chick hatches from the egg,fuse into the ploughshare bone. In the ostrich-like birds ^HH^H ^HHj ^H M HHwH IP ■pi ^ ■-; I^^^^^^H 1 ^^^K i^kL. f 11 s i 1 ^^^ WF \ -^Jl ^-^ m ^H V -^ fl V^ H ■ 1 JH^^I 1 ^ 1 Fig. 317.— of Bald Eagle, showing greater fusion and morespecialization than in Fig. 316. these small bones never fuse, but remain separate through-out life—a reptilian character persistent in these strangebirds (Fig .316). The ploughshare bone is seen splendidlydeveloped in such a bird of strong flight as the Bald that we have explained the origin of the tail,let us consider what part it plays in the lives of the birdsabout us. So diverse are the modes of life, and so variedare the surroundings of this class of creatures, that we 404 The Bird ^^> ^ ■ ^-^^^^^l^^l ^v k ^^H ^^nu / ^t ^^^^H HP i ■ii ,y[^Bl< ^ ^^^^^^^^^^^^1 ^^^^^^^^^^^B^^*2L ^^L^li .^^^^1 ■ ^^1 Fig. 318.—Fan-tailed Pigeon, showing extreme development of ,1 > .ev <\.--■ ^ ■ -< . v**. FiQ. 319.—Emeu, a tailless bird. (Courtesy of N. Y. Zoological Society.) Tails 405 shall find many unexpected uses to which the tail is put,and yet those which have been explained are a mere frac-tion of the problems which still await solution. The principal use of the tail-feathers in birds is, ofcourse, to perform the function of a rudder, and we findthat the arrangement of the bones perfectly carries outthe simile of a tail to the rudder of a ship; namely, abroad, expanded surface which is closely hinged to the
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Keywords: ., bookcentury1900, bookdecade1900, booksubjectbirds, bookyear1906
