. The cyclopædia of anatomy and physiology. Anatomy; Physiology; Zoology. Digestive canal of an Eagle. In those birds, again, the food of which is exclusively of the vegetable kind, as grains and seeds, and of which consequently a great quantity must be taken to produce the ade- quate supply of nutriment, and where the cavity of the gizzard is very much diminished by the enormous thickness of its muscular coat, the crop is more developed, and takes a more important share in the digestive process. Instead of a gradual cylindrical lateral dila- tation of the gullet, it assumes the form of a glob
. The cyclopædia of anatomy and physiology. Anatomy; Physiology; Zoology. Digestive canal of an Eagle. In those birds, again, the food of which is exclusively of the vegetable kind, as grains and seeds, and of which consequently a great quantity must be taken to produce the ade- quate supply of nutriment, and where the cavity of the gizzard is very much diminished by the enormous thickness of its muscular coat, the crop is more developed, and takes a more important share in the digestive process. Instead of a gradual cylindrical lateral dila- tation of the gullet, it assumes the form of a globular or oval receptacle appended to that tube, and rests upon the elastic fascia which connects the clavicles or two branches of the furculum together. In the common Fowl the crop is of large size and single (b,fig. 157 : I,fg. 171), but in Fig. the Pigeon it is double, consisting of two lateral oval cavities (b cjig. 158). The dilatation of the oesophagus to form the crop is more gradual in the Ducks than in the Gallinaceous birds. The crop is wanting in the Swans and Geese. The disposition of the muscular fibres of the crop is the same as in the oesophagus, but the muciparous follicles of the lining membrane are larger and more numerous. This difference is most conspicuous in the ingluvies of the grani- vorous birds, where it is not merely a temporary reservoir, but in which the food is mixed with the abundant secretion of the glands, and be- comes softened and macerated, and prepared for the triturating action of the gizzard and the sol- vent power of the gastric secretion. The change which the food undergoes in the crop is well known to bird-fanciers. If a Pigeon be allowed to swallow a great quan- tity of peas, they will swell to such an extent as almost to suffocate it. The time during which the food remains in the crop depends upon its nature. In a common Fowl animal food will be detained about eight hours, while half the quantity of vegetable substances will rema
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