XX. On the different structures and situations of the solvent glands in the digestive organs of, according to the nature of their food and particular modes of life
The solvent glands in birds are larger and more distinct from the other parts of the digestive organs than in the class mammalia, which has enabled me to ascertain many circumstances respecting their structure, not to be determined by examining the stomachs of quadrupeds. An account of these is contained in the present paper. To make the following descriptions more clear and distinct, I shall divide the digestive organs of birds, whether they live on animal or vegetable food, into four parts. The first, is the dilatation of the oesophagus, which forms a reservoir for the food, and which is called the crop. The second, is the part into which the ducts of the solvent glands open, which, I shall call the cardiac cavity. The third, is the cavity embraced by the digastric muscle, or gizzard. The fourth, is the space between the opening of the gizzard, and beginning of the duodenum, which I shall call the pyloric cavity, although in some instances it appears scarcely to deserve that name.