The œsophagus, Fig. 34, _e_, is long and of about the same diameter throughout except possibly for a slight enlargement of the anterior region where it leaves the pharynx. The two “olivary enlargements” mentioned by Chaffanjon (15) are not always present, and when seen were found to contain either food or small stones or both. The outside of the œsophagus is smooth and muscular while the lining is thrown into numerous longitudinal folds that in the empty œsophagus nearly obliterate the lumen; where distended by food or pebbles the longitudinal folds may be almost obliterated. In a thirty-inch animal the œsophagus is about six inches long, and opens suddenly, but without any apparent valve, into the large chamber of the stomach. The histology of the œsophagus and the other regions of the digestive tract will be described later. [Illustration: FIG. 34. DIGESTIVE SYSTEM OF A. MISSISSIPPIENSIS. _bd_, bile duct; _bs_, bile sac; _c_, cloaca; _e_, œsophagus; _f_, larger or fundic region of stomach; _h_, hyoid apparatus; _l_, liver; _p_, smaller or pyloric region of the stomach; _pa_, pancreas; _r_, rectum; _s_, small intestine; _t_, tongue; _tr_, trachea.] THE STOMACH The stomach, as is well known, is made up of two distinct parts; that on the animal’s left, into which the œsophagus opens, is many times larger than the part from which the small intestine leads. The larger or _fundic region_, Fig. 34, _f_, has, as will be described, very heavy muscular walls. When empty the lining of this part of the stomach is thrown into a few comparatively large folds, but when greatly distended with food, as it sometimes is, the internal folds are completely obliterated and the muscular layers are stretched until they have scarcely an eighth of their original thickness. In Figure 34 the stomach is considerably distended. The large region of the stomach frequently contains a number of stones, and for that reason, probably, is sometimes spoken of as the gizzard. In one thirty-inch alligator fourteen pebbles of irregular shape, varying in largest diameter from four to seventeen mm. and aggregating six grams in weight, were found. Voeltzkow (78) says that gastroliths of two to three cm. diameter are found in the stomach of the adult Madagascar crocodile. Neither the transverse fold nor the smooth, lateral disks (or shields) described by Chaffanjon could be seen in either the empty or in the distended stomach. The _smaller part_ of the stomach, Fig. 34, _p_, lies to the right and somewhat ventrad to the anterior region of the larger part, near the entrance to the œsophagus. It connects by a fairly large opening with the larger part of the stomach, and by a smaller opening with the duodenum. The former opening apparently has no valve, unless it be a slight sphincter muscle; the latter is guarded by a pair of thickened lips, called by Chaffanjon “semilunar valves.”