The pylorus, py, opens into a small, pointed, thin-walled diverticulum, di, and, at the same time, into the duodenum, d. The diverticulum noted, also, in connection with figure 7, has relatively thick, wrinkled walls; its significance is not known to the writer. From this diverticulum the duodenum, d, leads caudad and laterad for a short distance as a narrow tube, then suddenly expands into the widest part of the entire intestine. Into this wide part of the duodenum, 3 or 4 mm. from the pylorus, opens the bile duct, bd. The bile sac, bs, is an elongated oval body with thin walls, lying to the right of the pylorus, its connection with the liver was not seen.
Lying between the anterior end of the duodenum and the posterior end of the stomach, and extending caudad for 10 to 15 mm., in the median plane of the animal is the pancreas, pan. It is a long narrow body of a whitish color; its duct or ducts could not be determined by dissection. The duodenum extends caudad, with gradually diminishing caliber, from the enlarged region mentioned above. About 10 to 15 mm. caudad to the stomach it makes a sort of double loop to the right, a wide loop, lp, and a close one, lp´, nearer the median plane. From the latter loop the intestine extends straight to the left, for a distance of about 10 mm., where it makes a small loop cephalad, lp2, and then opens to the yolk-sac, y. The yolk-sac is shown here simply as an irregular piece of tissue, the yolk having been removed.
The anterior intestinal portal, aip, and posterior intestinal portal, pip, are in close proximity with each other.
From the posterior intestinal portal the intestine extends straight cephalad to the posterior end of the stomach, dorsal to which it forms a double loop, a wider one, lp3, and a narrow one, lp4. From the latter loop, lp4, the intestine extends straight caudad, parallel and near to the straight region leading from the posterior intestinal portal, until it reaches the region of the loop lp2, dorsal to which it forms a small loop, lp5. From loop lp5 the intestine, which is here of very small caliber, extends caudad for about 10 mm., where it forms another indistinctly double loop, lp6.
From loop lp6 the large intestine, il, extends, with gradually increasing caliber, to the cloaca, cl, a distance of 10 to 15 mm.
Except in the enlarged region near the pylorus the lumen of the intestine is almost obliterated by the folding of its thick walls, so that little or nothing can be told of its lining with the naked eye.
A distinct mesentery holds the loops of the intestine in position and binds the entire enteron close to the dorsal body wall. Because of the lack of properly fixed tissue no sections of the enteron of this stage were made.
[REFERENCES]
1. Bronn, H. G.: Klassen des Thier-Reichs. (Vols. on reptiles.) 1890.
2. Chaffanjon, V.: Observations sur Alligator mississippiensis (Tractus intestinalis und Mesenterium). Ann. Soc. Linn. Lyon, vol. 28, p. 83 ff., 1881.