. Cuvier's animal kingdom : arranged according to its organization. Animals. 154 AVES. Many of the cold-blooded Ovipara do not bring forth their young until they are developed and extricated from their shell, or other membranes which separated them from their parent. These are called/«/^e Ovipara. THE SECOND CLASS OF VERTEBRATED ANIMALS. THE BIRDS {AVES),— Are o^-iparous vertebrates with double circulation and respiration, [mostly] organized for flight. Their lungs, undivided and attached to the ribs, are enveloped by a membrane pierced with large holes, and which allows the air to pass into m
. Cuvier's animal kingdom : arranged according to its organization. Animals. 154 AVES. Many of the cold-blooded Ovipara do not bring forth their young until they are developed and extricated from their shell, or other membranes which separated them from their parent. These are called/«/^e Ovipara. THE SECOND CLASS OF VERTEBRATED ANIMALS. THE BIRDS {AVES),— Are o^-iparous vertebrates with double circulation and respiration, [mostly] organized for flight. Their lungs, undivided and attached to the ribs, are enveloped by a membrane pierced with large holes, and which allows the air to pass into many cavities of the chest, the abdominal region, arm-pits, and even of the interior of the bones* ; so that the ambient fluid not only bathes the surface of the pulmonary vessels, but also that of an infinitude of vessels traversing the rest of the body. Thus Birds respire, in certain respects, by the ramifications of their aorta, as well as by those of their pulmonar)^ artery, and the energy of their irritability is in proportion to their amount of respiration, t Their total conformation is arranged to participate in this energy. Their anterior extremities, destined to sustain them in flight, could neither serve them for standing, nor for clutching : they are bipeds, then, and pick up objects from the earth with their mouth ; their body, consequently, is balanced upon the legs ; the thighs are directed forv\-ard, and the toes are lengthened to form a suflîcient base for standing. The pehds is longitudi- nally much extended, to furnish attachment to the muscles which support the trunk upon the thighs : there is even a suite of muscles proceeding from the pelvis to the toes ; and passing over the knee and heel, so that the simple weight of the bird flexes the toes : it is thus that they are enabled to sleep perched on one foot. The ischia, and especially the ossa pubis, are lengthened out behind, and widened in their span, to allov*' the necessary space for the developement
Size: 1029px × 2427px
Photo credit: © The Book Worm / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookcentury1800, bookdecade1840, bookpublishe, booksubjectanimals
