190 The Allicrator and Its Allies 



the feeding season is that the scaly epithelium with 

 which it is covered is somewhat thicker and more 

 compact in the former than in the latter condition, 

 though even this difference may have been due to 

 differences in the ages of the animals used. The 

 base of the tongue differs from the tip in having 

 a thicker epithelium and in having compound 

 tubulo-alveolar glands. These glands in the hiber- 

 nating animal have many more alveoli than in the 

 feeding animal, though this, again, may have been 

 due to the difference in age. 



The lining of the roof of the mouth is essentially 

 the same as that of the tongue. The glands are 

 found only in the posterior region. The slight 

 differences in tha papillse here found may easily 

 be due to the difference in age. 



The oesophagus shows the usual layers for that 

 region. Its epithelium is partly ciliated in the 

 anterior part. The muscularis mucosa is very 

 scant in the anterior region. The only difference 

 between the two stages is that in the feeding the 

 muscularis mucosa in the anterior region is much 

 more strongly developed than in the hibernating 

 stage; and in the former the nuclei of the epi- 

 thelium are not arranged in two zones as in the 

 latter. 



The stomach has the usual layers, and has es- 

 sentially the same structure in the three regions 

 studied, except that the wall in the fundic region 

 is much the thickest, due mainly to the great 



