. 



*o\. .? 



e-- 



TONGUE. 



Fig. 756. 



TONGUE. 



Fig. 758. 



Fig. 756. Fungiform papilla covered by the epithelium e on one side, and with the secondary or simple papillae p. 

 Magnified 35 diameters. 



Fig. 757. The same, with the vessels ; the epithelium e represented in outline, a, artery ; v, vein ; d, capillary loops 

 of the simple papilla ; e, capillaries in the simple papillae of the mucous membrane at the base of the fungiform 

 papilla. Magnified 18 diameters. 



Fig. 758. Perpendicular section of a human circumvallate papilla. A, proper papilla ; B, wall ; a, epithelium ; b b, 

 nerves of the papilla and wall ; c, secondary papillae. Magnified 10 diameters. 



Fig. 759. Follicular gland from the root of the human tongue, a, epithelium ; b, papillae of the mucous membrane ; 

 c, areolar coat ; e, cavity ; /, epithelium lining it ; g g, follicles in the thick capsule. Magnified 30 diameters. 



The fungiform or clavate papillae (fig. 756) 

 are reddish, distributed over the entire sur- 

 face of the tongue, and are very nume- 

 rous at its point. Each has at its base 

 a club-shaped mucous papilla, and is covered 

 all over with simple or secondary conical 

 papillae (p p], and a simple epithelial layer 

 (e), without filiform processes. The vessels 

 are more numerous, but otherwise resemble 

 those in the filiform papillae (fig. 757). 



The circumvallate or lenticular papillae 

 (fig. 758) consist of a flattened central pa- 

 pilla (A), surrounded by an elevated wall or 

 ridge (B). The flat surface is furnished with 

 crowded conical secondary papillae (c), the 

 whole being covered with epithelium (a) free 

 from processes. The wall appears as a 

 simple fold of the mucous membrane, and 

 also exhibits beneath its smooth epithelial 

 coat numerous rows of simple, conical se- 

 condary papillae. In other respects these 

 papillae do not differ essentially in structure 

 from the fungiform. 



In some of the papillae of the tongue axial 

 bodies are found resembling those in the 

 papillae of the skin. 



The epithelial processes of the filiform 

 papillae are often covered by a fungus (Lep- 

 tothrix}, the mycelium closely surrounding 

 them, whilst some of the filaments project 

 from the surface. 



The glands of the tongue consist of mucous 

 and follicular glands. 



The mucous glands resemble those of the 

 mouth (MOUTH). 



The follicular glands are most numerous 

 between the epiglottis and the circumvallate 

 papillae, and are so superficially situated as 

 to form projections of the mucous membrane. 

 They form lenticular or globular masses, 

 from 1-24 to 1-6" in diameter, imbedded in 

 the submucous tissue, and in the middle of 

 the free surface is the orifice (759 d] of a co- 

 nical cavity (e), formed by a depression of 

 the mucous membrane. Each gland forms a 

 thick-walled capsule, surrounded by a fibrous 



