. Natural history of the animal kingdom for the use of young people : in three parts, comprising I. Mammalia : II. Birds : Part III. Reptiles, amphibia, fishes, insects, worms, molluscs, zoophytes, &c. : with 91 coloured plates, including about 850 figures, and numerous additional illustrations in the text . ds are the conversion of the frontlimbs into organs of flight, and the feathery coveringof the whole body, which replaces the hairy coatingof mammals. These feathers are gradually thrown off, andare replaced by new ones, at least once a generally takes place in autumn, and is cal
. Natural history of the animal kingdom for the use of young people : in three parts, comprising I. Mammalia : II. Birds : Part III. Reptiles, amphibia, fishes, insects, worms, molluscs, zoophytes, &c. : with 91 coloured plates, including about 850 figures, and numerous additional illustrations in the text . ds are the conversion of the frontlimbs into organs of flight, and the feathery coveringof the whole body, which replaces the hairy coatingof mammals. These feathers are gradually thrown off, andare replaced by new ones, at least once a generally takes place in autumn, and is calk-dmoulting. A fully developedfeather consists of thequill, the s h a ft andthe vane. The vaneconsists of many thinlayers , called barbs,which are linked to-gether by fine hookedprocesses. The feathers arc not found upon all portions of the skin, but on definite spaces, which are calledPterylae or feather-tracts. The head is usually covered with feathers. One feather - tract extends on the lower side of the neck to the breast. There the feather-tracts fork. A similar feather- Skeleton of Bearded Vullure tract commences behind the head, and extends over the whole back to the tail. The feathers are so arranged, that, although placed on definite tracts, they form a protective covering to the whole The bare or downy spaces (Apteria), are veryservice; ble to the bird, for they enable it to moveits head and neck in all directions, and to cover itshead when it sleeps. The wings, or fore limbs of birds are con-structed on the same model as the fore limbs ofmammals. They consist of arm, forearm, and wings are furnished with a series of long andstrong feathers (quills), which serve for hand is composed of a thumb and two fingersonly, and the thumb with its clothing of feathers iscalled the Alula or bastard-wing. The direction inflight is chiefly guided by the tail-feathers. Wing-bones of Bird. nw e 5
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Keywords: ., bookcentury1800, bookpublisherlondon, booksub, booksubjectzoology
