. Beginners' Zoology . Fig. 288. —Hand, Wrist ^u), Forearm, andElbow of Young Chick (after Parker). 154 BEGINNERS ZOOLOGY. Fig. 289. — Breast-bone AND Shoul-der Bones ofCassowary, five carpals of the chick being reduced to two in the fow^(Figs. 287, 288). The thumb or first digit has a coveringof skin separate from that of the otherdigits, as may be seen in a plucked degenerate hand of the fowl is ofcourse useless as a hand (what servesin its place?) but it is well fitted forfirm support of the feathers in flying. Thetwo bones of the forearm are also firmlyjoined. There are eighteen m
. Beginners' Zoology . Fig. 288. —Hand, Wrist ^u), Forearm, andElbow of Young Chick (after Parker). 154 BEGINNERS ZOOLOGY. Fig. 289. — Breast-bone AND Shoul-der Bones ofCassowary, five carpals of the chick being reduced to two in the fow^(Figs. 287, 288). The thumb or first digit has a coveringof skin separate from that of the otherdigits, as may be seen in a plucked degenerate hand of the fowl is ofcourse useless as a hand (what servesin its place?) but it is well fitted forfirm support of the feathers in flying. Thetwo bones of the forearm are also firmlyjoined. There are eighteen movablejoints in our arm and hand. The birdhas only the three joints which enableit to fold its wing. The wrist joint isthe 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 Jaws. How does theirshape adapt them to this use} Forthe same reason the Jieck of a birdsurpasses the necks of all other ani-mals in what respect? Is the trunkof a birdflexible orinflexible }There isthus )- relation between struc-ture of neck and
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Keywords: ., bookcentury1900, bookdecade1920, bookidbeginnerszoo, bookyear1922
