434 



PRACTICAL ANATOMY. 



sides and tips are in contact with the lingual surfaces of 

 the upper teeth. Tt is covered by mucous membrane, in 

 which are imbedded the organs of taste. The mucous 

 membrane invests the dorsum, lateral surfaces, and tip, 

 from which it is reflected to the floor of the mouth, 

 forming its fraenum. It is composed of two principal 

 layers, the cutis vera and epidermis. The cutis vera is 

 a strong, fibrous, papillary structure intimately adherent 

 to the muscular tissues of the tongue. The epiderm is 

 epithelial in character. The papillae of the tongue are 



FIG. 191. STRUCTURE OF THE GUSTATORY ORGANS. 



I. Transverse section of :\ circumvallate papilla : W, the papilla : v, v, the wall in sec- 

 tion ; R, R, the circular split of fbssa ; K, K, the taste-bulbs in position ; N, N, the nerves. 

 II. Isolated taste-bulbs: D. supporting or protective cells; k, under end : E. free end open, 

 with the projecting apices of the taste-cells. III. Isolated protective cells, d, with a taste- 

 cell, e. 



prominent and very abundant, and are divided into three 

 classes, the fimgiform, the filiform, and the circumval- 

 latae. The fungiform are papillary elevations, about the 

 size of a mustard-seed, scattered over the dorsum of the 

 tongue. They are deep red in color, and are seen princi- 

 pally at the sides and tip. The filiform papillee give to 

 the mucous membrane its velvety appearance. They are 

 very numerous, especially at the anterior two-thirds of the 

 tongue. They are arranged in rows, which run outward 

 and forward from the median line of the tongue, and 



