Figure 43 represents the epithelium from the anterior region as seen under high magnification. The outlines of all the cells could not be determined but if each nucleus represents a cell there are twenty-five or thirty layers of cells. The nuclei are arranged in two dense, irregular groups, one along the base of the epithelium, the other about two thirds of the distance from the base to the free border. The basal nuclei are perhaps slightly larger and more rounded than those of the distal group. Between these two groups are numerous more scattered nuclei; while scattered through the epithelium, except near the free border, are smaller, round nuclei that stain somewhat darker than the rest; these, from their size and appearance, seem possibly to belong to an invisible network of connective tissue that has penetrated the epithelium from the surrounding mucosa. [Illustration: FIG. 43. The epithelium of the anterior region of the œsophagus of the hibernating animal, under high magnification.] The free border of the epithelium consists of long, ciliated, columnar cells in which the cell walls may be easily seen. The cilia are of average length and even in this anterior region are not everywhere present; possibly they are arranged in bands, but the material at hand was not sufficient to determine this. As was noted above, cilia are wanting in the posterior region. The only differences noted in the anterior region of the œsophagus between the feeding and the hibernating conditions are in the muscularis mucosa and the epithelium. As was noted above, the muscularis mucosa is practically absent in the hibernating stage, being represented only by a few small, scattered bundles of longitudinal muscle fibers; while in the feeding stage there is a narrow but fairly distinct layer to represent the muscularis mucosa. [Illustration: FIG. 44. The epithelium of the anterior region of the œsophagus of the feeding animal, under high magnification.] The difference in the appearance of the epithelium is not striking. The nuclei are somewhat larger in the feeding stage and, instead of being crowded into a basal and a median zone, as noted in the hibernating conditions, they form a dense basal zone, but show no indication of medial zone. From the dense basal zone the nuclei become more scattered towards the free surface and are rarely found closer to the surface than is shown in Figure 44. The smaller nuclei scattered among the larger ones, noted in connection with the hibernating stage, are not here seen. As in the hibernating stage cilia are present on some but not all cells of this region. The only noticeable difference between the feeding and hibernating conditions of the posterior region of the œsophagus is in the epithelium, which, as in the feeding condition of the anterior œsophagus, exhibits but one zone of closely set nuclei, that at the base of the epithelium.