PAPILLAE OF THE TONGUE. 



73 



Fig. 198.* 



They vary in shape somewhat, but for the most part 

 are conical or filiform, and covered by a thick layer of 

 epidermis, which is arranged over them, either in an im- 

 bricated manner, or 

 is prolonged from 

 their surface in the 

 form of fine stiff pro- 

 jections, hair-like in 

 appearance, and in 

 some instances in 

 structure also (fig. 

 198). From their 

 peculiar structure, it 

 seems likely that 

 these papillae have 

 a mechanical func- 

 tion, or one allied 

 to that of touch, 

 rather than of taste ; 

 the latter sense be- 

 ing probably seated 

 especially in the \ 

 other two varieties of 

 papillae, the circum- 

 vallate and the fungi- 

 form, 



The epithelium of 

 the tongue is of the 

 squamous or tesselated kind, like the epidermis (p. 422). 

 It covers every part of the surface; but over the fungiform 



* Fig. 198. Two filiform papillae, one with epithelium, the other 

 without (from Kolliker, after Todd and Bowman). y. P> the substance 

 of the papillae dividing at their upper extremities into secondary papillae ; 

 a, artery, and 0, vein, dividing into capillary loops ; e, epithelial cover- 

 ing, laminated between the papillae, but extended into hair-like pro- 

 cesses/, from the extremities of the secondary papilla. 



