In the Goose, genus _Anser_ (Fig. 65), we find the bill short, not longer than the head, conical, covered at the base with a cerous skin, with under mandible smaller than the upper. In the Sparrows, _Passerina_ (Fig. 66), the bill is strong and conical, the upper mandible slightly curved, the lower compressed and smaller than the upper; nostrils lateral, basal, round, and partly concealed by the short feathers at the base of the mandibles. In the Goatsuckers, _Caprimulgus_ (Fig. 67), the bill is remarkably small and weak, the sides inflexed and sometimes gaping. [Illustration: Fig. 65.] [Illustration: Fig. 66.] [Illustration: Fig. 67.] The tongue, like the bill, however, is only an accessory to the digestive apparatus; for while the beak serves the purpose of prehension and trituration, the tongue assists in deglutition or swallowing. Digestion is so active in some birds, that they get fat in an excessively short space of time. The Ortolan Bunting, _Emberiza hortulana_, and some others, are fattened for the table in five or six days. In the swelling under the throat, called the crop, _a_ (Fig. 68), or first stomach, which is largely developed in some of the granivorous or grain-eating birds, the food remains for a time, where it undergoes certain modifications which facilitate digestion; thence it passes into the succenteric ventricle, or second stomach, _b_ (Fig. 68),--there it imbibes the necessary amount of gastric juice; being finally transformed into _chyme_ in the gizzard, _c_ (Fig. 68), or third stomach, which is possessed of great muscular power, being capable of acting upon the most solid bodies, triturating even the flints and gravel which the gallinaceous birds swallow to aid their digestion. [Illustration: Fig. 68.] It is a curious fact that a grain of seed, introduced into the stomach, may be digested without alteration, and ejected where it will germinate, if it meets with no obstacle to its vegetation. In this manner trees are frequently found in regions where their species appear to have been previously unknown. _Chyle_, which is a milky fluid formed from the junction of chyme and bile, is received by the small intestine, where the bile also flows from the liver and the saliva from the pancreas. The urinary apparatus consists of the kidneys, two in number, thick and irregular, and distinct one from the other, abutting on the intestine, which terminates in a species of pouch, or _cloaca_, through which evacuation, alternately of urine, excrement, and eggs, takes place. The sense of touch, of smell, of taste, and hearing are only slightly developed in birds. Some have spoken of great delicacy of scent in birds of prey, which are observed to assemble in great numbers on fields of battle and other places where human carcasses are exposed. But the opinions of naturalists, such as Audubon and Levaillant, seem to prove that these animals were attracted rather by the sight than smell.