. Key to North American birds [microform] : containing a concise account of every species of living and fossil bird at present known from the continent north of the Mexican and United States boundary, inclusive of Greenland. Birds; Ornithology; Oiseaux; Ornithologie. THE ANATOMY OF BIRDS.âPNEUMATOLOGY. 201 1111(1 tlic thoracic cavity proportionally enlarged; the air then rushes into tlie luncs and tho- racic rc'ccptiiclf's, while those of the abdomen become flaccid ; wlien tlie stenium is raised or approximated towards the spine, part of the air is expelled from the lungs and thonu-ic cells th
. Key to North American birds [microform] : containing a concise account of every species of living and fossil bird at present known from the continent north of the Mexican and United States boundary, inclusive of Greenland. Birds; Ornithology; Oiseaux; Ornithologie. THE ANATOMY OF BIRDS.âPNEUMATOLOGY. 201 1111(1 tlic thoracic cavity proportionally enlarged; the air then rushes into tlie luncs and tho- racic rc'ccptiiclf's, while those of the abdomen become flaccid ; wlien tlie stenium is raised or approximated towards the spine, part of the air is expelled from the lungs and thonu-ic cells thripiitrh the trachea, and part driven into the abdominal receptacles, which .are thus altcniately ciilariied and diminished with those of the thorax. Hence the lungs, notwithstanding their fixed condition, are subject to duo compression through the medium of the contiguous air- receptacles, and are affected equally and regularly by every inf>tion of the sternum and ribs. A lliinl use, and perhaps the one which is most closely related to the peculiar exigencies of the bird, is that of rendering the whole body specifically lighter; this must necessarily follow from tli(! desiccation of the luaiTow and other fluids in those spaces which are occupied by the air- cells, and by the rarification of the contained air from the heat of the IkkU". ... A fourth use (if the air-receptacles relates to the mechanical assistance which they afford to the muscles of tlie wings. This was suggested by (d)serviiig that an inflation of the air-cells in the gigantic crane (Cicoiiia argala) was followed by an extension of the wings, as the air f«iuud its way along the brachial and anti-brachial cells. In large birds, therefore, which, like the argala [or our wood ibis, Tanlulun lociihitor], hover with a sailing motion for a long-continued |H-riod in the upper regions of the air, the muscular exeition of keeping the wings outstretched will be lessened by the tendency of the distended air-ce
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Keywords: ., bookcentury1800, bookdecade1880, booksubjectbirds, bookyear1884
