. Animal and vegetable physiology, considered with reference to natural theology, by Peter Mark Roget ... Biology; Physiology; Plant physiology; Natural theology. RECEPTACLES FOR RETAINING FOOD. 179 Analogous in design to these pouches are the dilatations of the oesophagus of birds, deno- minated crops. In most birds which feed on grain, the crop is a capacious globular sac, placed in front of the throat and resting on the furcular bone. The crop of the Parrot is repre- sented at c, Fig. 29D; where, also, s indicates the cardiac portion of the stomach, and g the giz- zard, of that bird. The in
. Animal and vegetable physiology, considered with reference to natural theology, by Peter Mark Roget ... Biology; Physiology; Plant physiology; Natural theology. RECEPTACLES FOR RETAINING FOOD. 179 Analogous in design to these pouches are the dilatations of the oesophagus of birds, deno- minated crops. In most birds which feed on grain, the crop is a capacious globular sac, placed in front of the throat and resting on the furcular bone. The crop of the Parrot is repre- sented at c, Fig. 29D; where, also, s indicates the cardiac portion of the stomach, and g the giz- zard, of that bird. The inner coat of the crop is furnished with numerous glands, which pour out considerable quantities of fluid for macerating and softening the dry and hard texture of the grain, which, for that purpose, remains there for a considerable time. Many birds feed their young from the contents of the crop ; and, at those seasons, its glands are much enlarged, and very active in preparing their peculiar secretions : this is remarkably the case in the Pigeon (Fig. 300), which, instead of a single sac, is provided with two (seen at c, c. Fig. 300), one on each side of the oesophagus (o). The pouting pigeon has the faculty of filling these cavities with air, which produces that dis- tended appearance of the throat from which it derives its name. Birds of prey have, in general,. Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustrations may not perfectly resemble the original Roget, Peter Mark, 1779-1869. London : W. Pickering
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