The Œsophagus
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.
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.