118 



THE ALIMENTARY SYSTEM. 



face of the tongue the epithelium and tunica propria are thrown 

 up into papilla?, which are of three or four kinds filiform, 

 fungiform, circumvallate, and foliate. 



The filiform papilla are most numerous and thickly stud 

 the upper surface of the tongue. They consist of slender 

 papillary processes of the tunica propria, surmounted by 

 slender conical projections of epithelium, the cells of which at 

 the apex are horny and worn by attrition. 



The fwngiform papillce are larger and much less numerous 

 than the filiform, and are scattered about among the latter as 

 visible red points. They are lower, broader, and have blunt 



FIG. 50. 



P 



Circumvallate papillse, of rabbit (Ranvier). 

 p, fibrous core of papilla ; g, taste-buds ; n, nerves ; a, gland of Ebner. 



rounded tops. They consist of a connective-tissue core pro- 

 jecting from the tunica propria, with minute secondary pro- 

 jections from its surface, all covered with a layer of epithelium. 

 The circumvallate papillce are eight to twelve large broad 

 papillse arranged in a V shape at the base of the tongue. The 

 papilla? are similar to the fungiform. but are larger, and each 

 is surrounded by a deep furrow or ditch,, so that the papillse 



