Identifier: introductiontozo00wriguoft (find matches)
Title: An introduction to zoology : for the use of high schools
Year: 1889 (1880s)
Authors: Wright, R. Ramsay (Robert Ramsay), 1852-1933
Subjects: Zoology
Publisher: Toronto : Copp, Clark Co.
Contributing Library: OISE - University of Toronto
Digitizing Sponsor: MSN

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yx was apoor flier, (the stei-uuin has not been found, so we lack theevidence which would liave been forthcoming from it), but thehand was formed of three fingers with iuvlependent metacarpalsand stout claws, so it is likely that the anterior extremity musthave been of great service in climbing, the plumage serving,perhaps, more as a parachute than for true flight. lu thestructure of the hinder extremity there is no great diffeiencefrom that of a biid. 15. The Eatitfe or Cursorial Birds are unquestionably muchcloser to the Carinate Birds than Archseopteryx is; indeed many HIGH SCHOOL ZOOLOGY. 133 zoologists regard them as degenerate forms of carinato birds,which have iii the course of ages lost the power of flight, whileothers, looking at their s-lructure and theLr geographical distri-bution, think that they are a more primitive gioup than theCarinatje with more affinity to the reptiles, and that they neverpossessed the power of flight. The plumage in this group never piiiif^;5pi;;j^^
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Fist. 95. —Skeleton of the Moa (DinorniH). 134 HIGH SCHOOL ZOOLOGY. lias the cliaractor of contour or qiiill-foathors, tho plumes oftlio ostrich being nothing but gigantic downs. Instead of theboues of the head uniting early with each other, the sutures arcquite evident, and the cervical ribs are for a long time movable,instead of being coalesced with the vertebraj. Again, eitherthe )iubic or iscliiac bones or both may form a symj^hysis as theydo in most living reptiles ; and, at least, there is a greater re-semblance to the Dinosaur pelvis than thei-e is in tho carinatebirds. Other anatomical features of the Ratita3 are adaptive;the functionless nature of the fore-limbs is associated with thereduction in size of their bones and of the clavicles, while theadaptation of the hind limbs to rapid locomotion leads to a lossof one or two of the four toes. There is great structural diffei-ence between the families of Ratit.B, andthey are also marked oft geographically from each other. New

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