Fig. 35. A diagrammatic outline of the digestive tract of the alligator from the beginning of the œsophagus to the cloaca, to show the planes of the sections that were studied, _a.oes._, anterior œsophagus; _a.r._, anterior rectum; _a.s.i._, anterior small intestine; _c.st._, cardiac stomach; _f.st._, fundic stomach; _m.s.i._, middle small intestine; _p.oes._, posterior œsophagus; _p.r._, posterior rectum or cloaca; _p.s.i._, posterior small intestine; _p.st._, pyloric stomach.] Although carefully fixed in the usual fluids, the epithelial structures from this animal were not as clearly defined in most cases as could be desired; this rather unsatisfactory fixation may have been due to some physiological condition characteristic of the period of hibernation. That this was the case seems likely from the better fixation obtained by the same methods in the case of animals killed during the feeding season. The other animals from which tissues were taken were considerably smaller than the one mentioned above. They were killed early in the fall, after having been fed regularly for about five months upon bits of meat, both raw and cooked. _The Tongue._ The covering of the tongue was studied in two regions, near the free end, and towards the base. A section of the former region, drawn under high power, is shown in Figure 36. It consists of a dense mass of fibrous tissue, _a_, and small scattered cells, overlaid by a stratified epithelium of eight or ten layers. Only a small part of the fibrous base, just beneath the epithelium, is here shown. It is a dense areolar tissue with the elastic fibers apparently predominating. The epithelium, _e_, consists, as has just been said, of about eight or ten layers of cells, those at the base being generally cuboidal in shape, while towards the surface the cells become more and more flattened until at the surface they form a thick horny layer, _h_, in which no nuclei can be seen. The cells of the horny layer are flattened into mere fibers, which, at places, are seen projecting from the surface. The boundary between the horny cells and those beneath is quite distinct, though perhaps not quite so sharp as shown in the figure under discussion. [Illustration: FIG. 36. The covering of the anterior region of the tongue of the hibernating animal, under fairly high magnification; the plane of this section is not shown in Figure 35; _a_, areolar tissue; _e_, epithelium; _h_, horny layer of epithelium.] In a previous paper, the writer noted that the dorsum of the tongue is covered with small, evenly distributed papillæ, easily seen by aid of a hand lens. These so-called papillæ are here seen to be hardly papillæ at all, but small folds or wrinkles, although the epithelium is somewhat thickened at intervals. No glands are to be seen in this region of the tongue.