Tongue. 



15 



JZplulnttfs 



Corn 



341. The Upper Surface of the Tongue. 



At the dorsum of the tongue are three kinds of papillae, Papillae 

 gustatoriae (see Fig. 343)': 



a) Conical or filiform papillae, Papillae filiformes, are densely 

 set over the greater part of the dorsum of the tongue, in parallel rows, 

 which ^ run obliquely from the middle line forwards and outwards; they 

 have a thick epithelial covering, and contain a number of elastic fibres. 



b) Fungiform papillae, Papillae fungiformes, are scattered bet- 

 ween the filiform as large, rounded eminences ; their epithelial invest- 

 ment is very thin and they are covered 'with secondary papillae. 



c) Circumvalla te papillae, Papillae circumvallatae, eight to 

 fifteen in number, are arranged in two rows, which run obliquely back- 

 wards and inwards and meet in the middle line ; each is surrounded by 

 a layer of mucous membrane, and divided into several small papillae. 

 At the point of junction of the two rows, is the Foramen coecum. Behind 

 the circumvallate papillae are follicular glands, Glandulae lenticulares linguae. 



