The walls of the smaller part of the stomach are, as might be expected, much thinner than those of the larger region, but they are proportionately fairly thick and are internally thrown into numerous folds. THE INTESTINE In the intestine three regions may be distinguished: a long, considerably coiled small intestine; a wide, nearly straight rectum; and a short, wide cloaca. The _small intestine_, Fig. 34, _s_, is of moderate and rather uniform diameter, though somewhat thicker near the stomach, and is not coiled so extensively as figured by Chaffanjon. Near the stomach it receives the ducts of the liver and pancreas. The bile duct, Fig. 34, _bd_, is a continuation of an elongated bile sac, _bs_, which lies between the large right and smaller left lobes of the liver, _l_. The two main lobes of the liver, which appear smaller than in reality because of foreshortening in drawing, are connected, across the base of the œsophagus, by a narrow transverse band. The pancreas, _pa_, which is of fair size, lies partly dorsal to and partly in a narrow loop of the intestine, so that it is not very evident in a ventral view of the animal. The small intestine has heavy muscular walls whose histological structure will be described elsewhere. It opens abruptly, without any indication of a cæcum, into the large intestine or rectum. The _rectum_, _r_, is of about twice the diameter of the small intestine, though this, of course, varies with the amount of fecal matter it contains; it is nearly straight and possesses much thinner walls than the small intestine, though this, again, varies with the state of collapse or distention. At the posterior end of the rectum is a heavy sphincter valve separating that part of the intestine from the cloaca. The _cloaca_, _c_, is widest anteriorly where it is about as wide as the rectum; it gradually diminishes in diameter caudad, and appears flattened laterally. Its wall has the same general structure as the rectum, as will be described below. The mucous membrane posterior to the openings of the genital ducts is thrown into a more or less complete, ring-like transverse fold (Fig. 55 g.). In some species there may be a second, half-ring-like fold in the dorsal wall caudad to the more complete ring. The cloaca is divided by this fold into a larger anterior portion, g, and a shorter posterior portion, h; in the former the mucous membrane is thrown into a large number of small folds that in places form a network; in the latter the mucous membrane has a hard, thick epithelium, with a smooth surface and only a few longitudinal folds. The _ureters_ open, Fig. 55, _d_, _e_, at a moderate distance from each other, into the anterior region of the cloaca (about where the dorsal and lateral walls of this region come together). The _genital ducts_ (oviducts or vasa deferentia), _c_, _f_, on the other hand, open close together through the ventral wall of the posterior half of the cloaca, just in front of the copulatory organ.