File:A history of birds (1910) (14726752336).jpg

Identifier: historyofbirds00pycr (find matches)
Title: A history of birds
Year: 1910 (1910s)
Authors: Pycraft, W. P. (William Plane), 1868-1942
Subjects: Birds
Publisher: London, Methuen and Co
Contributing Library: American Museum of Natural History Library
Digitizing Sponsor: Biodiversity Heritage Library

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two particulars—each terminated in a large claw, and the thirdfinger had as many as four phalanges, or separate segments,as against a single phalanx in modern birds. Claws occur to-day only on the thumb and second finger, and here they are
Text Appearing After Image:
STRUCTURAL ADAPTATIONS 177 reduced to mere vestiges, save only in the remarkable Hoatzin(Opistkocouius cristatus). In this bird, as we have alreadypointed out, they are during the nestling period of considerablesize, but later they become absorbed. Ducks and Accipitres re-tain vestiges of these claws throughout life ; in other birds theyhave either become entirely suppressed on one or both digits, orthey appear only during embryonic life. In the young Ostrich,however, a vestigal claw has been found on the third digit. This reduction in the number of the digits, and the weldingtogether which they have undergone, has resulted in the forma-tion of what may be described as a jointed rod, eminently adapted

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