The chief peculiarity of the small intestine is the apparent entire absence of the submucosa. Goblet cells are also wanting. The greater diameter of the anterior region is due both to the greater diameter of the lumen and to the greater thickness of the walls. The middle and posterior regions have about the same diameter, though the mucosa becomes thinner and less complicated caudad. There is practically no difference between the hibernating and feeding stages. The anterior and posterior regions of the large intestine have essentially the same structure. No difference can be seen between the hibernating and feeding conditions. CHAPTER VI THE UROGENITAL ORGANS Figure 54 represents the urogenital apparatus of a thirty-inch female specimen of _Alligator mississippiensis_. Figure 55 shows the corresponding organs of a male _A. lucius_; reproduced from Bronn. The urogenital organs in the young animal are so similar in the two sexes that one might easily be mistaken for the other; of course in sexually mature animals, especially during the breeding season, this is not the case. The _kidneys_, Fig. 54, k, Fig. 55, a, are flattened, lobulated organs lying against the dorsal body wall. The large anterior lobe of each kidney is pointed at its anterior end and lies at some little distance from its fellow; it is partially divided into secondary lobes and is traversed on its ventral surface by branching blood-vessels. Its antero-medial border is sometimes partially concealed, in a ventral view, by the elongated gonad of that side. Caudad to the main lobe of the kidney is a smaller, usually distinct, lobe in contact mesially with its fellow of the opposite side. A fairly wide _ureter_, Fig. 54, u, Fig. 55, d, extends from the posterior end of each kidney to open (Fig. 54, u¹, Fig. 55, e) into the anterior region of the cloaca, as described in connection with the digestive system. The _ovary_, Fig. 54, o, as noted above and as seen in Figs. 54 and 55, in the young animal is of practically the same shape as the testis. The ova at this stage are of microscopic size and are hence not visible to the naked eye. The ovary, even at this stage, is more or less distinctly marked off into lobules by a series of small grooves. [Illustration: FIG. 54. FEMALE UROGENITAL SYSTEM. _f_, oviduct; _f¹_, opening of oviduct; _k_, kidney; _m_, mesentery; _o_, ovary; _u_, ureter; _u¹_, opening of ureter.]