172 The Alligator and Its Allies 



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 

 slightl}^ larger and more 

 rounded than those of 

 the distal group. Be- 



m0: 



M' 



?/.'S 





M 



lii^ 



tween these two groups 

 are numerous more scat- 

 tered 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 possi- 

 bly to belong to an invisible network of connective 

 tissue that has penetrated the epithelium from the 

 surrounding mucosa. 



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 





Fig. 43. The epithelium of the 

 anterior region of the oesophagus 

 of the hibernating animal, under 

 high magnification. 



