. Key to North American birds. 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 and Lower California, with which are incorporated General ornithology: an outline of the structure and classification of birds; and Field ornithology, a manual of collecting, preparing, and preserving birds. Birds; Birds. THE ANATOMY OF BIRDS. —PNEUMATOLOGY. 201- and the thoracic cavity proportionally enlarged; the air then rushes into the lungs and tho- racic receptacles, while those o
. Key to North American birds. 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 and Lower California, with which are incorporated General ornithology: an outline of the structure and classification of birds; and Field ornithology, a manual of collecting, preparing, and preserving birds. Birds; Birds. THE ANATOMY OF BIRDS. —PNEUMATOLOGY. 201- and the thoracic cavity proportionally enlarged; the air then rushes into the lungs and tho- racic receptacles, while those of the abdomen become flaccid; when the sternum is raised or approximated towards the spine, part of the air is expelled from the lungs and thoracic cells through the trachea, and part driven into the abdominal receptacles, which are thus alternately enlarged and diminished with those of the thorax. Hence the lungs, notwithstanding their fixed condition, are subject to due compression through the medium of the contiguous air- receptacles, and are affected equally and regularly by every motion of the sternum and ribs. A ihii-d 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 the desiccation of the marrow 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 body. ... A fourth use of the air-receptacles relates to the mechanical assistance which they afford to the muscles of the wings. This was suggested by observing that an inflation of the air-cells in the gigantic crane {Oiconia argala) was followed by an extension of the wings, as the air found its way along the brachial and anti-brachial cells. In large bii-ds, therefore, which, like the argala [or our wood ibis, Tantalus loeulator], hover with a sailing motion for a long-continued period in the upper regio
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Keywords: ., bookcentury1800, bookdecade1890, booksubjectbirds, bookyear1894
