. Beginners zoology. Zoology. Fig. 289. — Breast- bone AND Shoul- der Bones of Cassowary. Arvf>i five carpals of the chick being reduced to two in the fowl (Figs. 287, 288). The thumb or first digit has a covering of skin separate from that of the other digits, as may be seen in a plucked bird. The degenerate hand of the fowl is of course useless as a hand (what serves in its place?) but it is well fitted for firm support of the feathers in flying. The two bones of the forearm are also firmly joined. There are eighteen movable joints in our arm and hand. The bird has only the three joints w
. Beginners zoology. Zoology. Fig. 289. — Breast- bone AND Shoul- der Bones of Cassowary. Arvf>i five carpals of the chick being reduced to two in the fowl (Figs. 287, 288). The thumb or first digit has a covering of skin separate from that of the other digits, as may be seen in a plucked bird. The degenerate hand of the fowl is of course useless as a hand (what serves in its place?) but it is well fitted for firm support of the feathers in flying. The two bones of the forearm are also firmly joined. There are eighteen movable joints in our arm and hand. The bird has only the three joints which enable it to fold its wing. The wrist joint is the joint in the forward angle of the wing. Since the fore limbs are taken up with loco- motion, the grasping function has been as- sumed by the jazvs. How does their shape adapt them to this use} For the same reason the neck of a bird surpasses the necks of all other ani- mals in what respect? Is the trunk of a bird flexible or inflexible.'' There is thus "A. cor- relation between struc- ture of neck and trunk. Explain. The same correlation is found in which of the reptiles .-* (Why does rigidity of trunk require flexibility of neck ?) Why does. Fig. 290. — A Fossil Bird (archaopferyx) found in the rocks of a former geological epoch. Question: Find two resemblances to reptiles m this extinct bird absent from skeletonsof extant Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustrations may not perfectly resemble the original Coleman, Walter M. Toronto : Macmillan
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Keywords: ., bookcentury1900, bookdecade1920, booksubjectzoology, bookyear1921
