Handbook of field and general ornithology; a manual of the structure and classification of birds (1890) (14726978436)

Identifier: handbookoffieldg00coue (find matches)
Title: Handbook of field and general ornithology; a manual of the structure and classification of birds
Year: 1890 (1890s)
Authors: Coues, Elliott, 1842-1899
Subjects: Birds -- Collection and preservation Birds -- Classification Birds -- Anatomy
Publisher: London, Macmillan
Contributing Library: American Museum of Natural History Library
Digitizing Sponsor: Biodiversity Heritage Library



Text Appearing Before Image:
, neural spine ; r, pleurapophysis, orvertebral part of a free rib, bearing v, uncinateprocess or epipleura; cr, heemapophysis orsternal part of the same ; st, section of sternumor breast-bone (hremal spine). Designed by Dr.R. W. Shufeldt, U.S.A. hole in the humerus. Pneumaticity is not directly nor necessarilyrelated to power of flight; some birds which do not fly at all aremore pneumatic than some of the most buoyant. (On the generalpneumaticity of the body see beyond, under head of the RespiratorySystem.) The Axial Skeleton (Figs. 54, 55, 56) of a bird or any vertebratedanimal, that is, one having a back-bone, exhibits in cross-section tworings or hoops, one above and the other below a central point, likethe upper and lower loops of a figure 8. The upper ring is theneural arch (Gr. vevpov, neuron, a nerve), so called because such a ANATOMY OF BIRDS cylinder encloses a section of the cerebro-spinal axis, or principalnervous system of a vertebrate (brain and spinal cord, whence arise
Text Appearing After Image:
all the nerves of the body, excepting those of the sympatheticnervous system). The lower ring is the hcemal arch (Gr. af/xa^ halma, GENERAL ORNITHOLOGY blood), which similarly contains a section of the principal blood-vessels and viscera. Fig. 55 shows such a section, made across thethoracic or chest region of the trunk. Here the upper ring (neural)is contracted, only surrounding the slender spinal cord, while thelower ring is expanded to enclose the heart and lungs. Such asection, made in the region of the skull, Avould show the reverse ;the upper ring greatly inflated to contain the brain, the lower con-tracted and otherwise greatly modified into bones of the jaws. Thusthe trunk of a vertebrate is a double-barrelled tube; one tubeabove for the axial nervous system, the other below for the visceraat large ; the partition between the two being a jointed chain ofsolid bones from one end of the body to the other. These solidbones are the centrums or bodies of vertebra, in the trunk; and