TONGUE. 



[ 771 ] 



TONGUE. 



papillae do not differ essentially in structure 

 from the fungiform. 



In some of the papillse 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- 

 tothriv}, the mycelium closely surrounding 

 them, whilst some of the filaments project 

 from the surface. 



Fig. 755. 



Two human filiform papillse, one with epithelium. 

 p, p, papillae; a, v, artery and vein, with the capillary 

 loops ; e, epithelial covering ; f, its processes. 



Magnified 35 diameters. 



The glands of the tongue consist of mu- 

 cous and follicular glands. 



The mucous glands resemble those of the 

 mouth (MOUTH). 



The follicular glands are most numerous 

 between the epiglottis and the circumval- 

 late papillae, and are so superficially situated 

 as to form projections of the mucous mem- 

 brane. They form lenticular or globular 

 masses, from 1-24 to 1-6" in diameter, im- 



bedded in the submucous tissue ; and in the 

 middle of the free surface is the orifice 

 (754 d) of a conical cavity (e), formed by a 

 depression of the mucous membrane. Each 

 gland forms a thick-walled capsule, sur- 

 rounded by a fibrous coat (c) continuous 

 with the deeper portion of the mucous 

 membrane, and lined internally by a pro- 

 longation of the mucous membrane with 

 papillae and epithelium (b, a) ; and between 

 the two are closed capsules or follicles (^), 

 imbedded in a fibrous and vascular basis. 

 The follicles are from 1-120 to 1-48" in 

 diameter, rounded or somewhat elongate, 

 whitish, composed of a coat of connective 

 tissue without elastic fibres, and with grey- 

 ish-white contents consisting of cells 1-60CO 

 to 1-4000" in diameter and free nuclei. 



In the small portion of tissue constituting 

 one of the papillae of the frog's tongue, 

 Beale found striped muscular fibres, capil- 

 lary vessels, purely sensitive nervous fibres 

 forming an expanded terminal plexus at the 

 summit of the papilla, motor nerve-fibres 

 distributed to the muscle, nerve-fibres 

 around the capillary vessels, and a few very 

 fine nerve-fibres ramifying in different parts 

 of the papillae. All of these are imbedded 

 in and held together by connective tissue, 

 forming the body of the papilla, the summit 

 of which is surmounted by a peculiar epithe- 

 lium-like tissue, perhaps connected with 

 the nerves and belonging to nerve-texture, 

 while its sides are covered with ordinary 

 ciliated epithelium. The fur of the tongue, 

 which is usually considered to be composed 

 of epithelium, is stated by Butlin to consist 

 of Schizomycetous fungi. 



BIBL. Todd and Bowman, Phys. ; Ward, 

 Todtfs Cycl. An. $ Phys.\ Salter, ibid.-, 

 Huxley, Mic. Jn. ii. 74; Beale, Phil. Tr. 

 1864, and How fyc. ; Hartmann, Mutter's 

 Archiv, 1863 ; Klein and Verson, Strieker's 

 Hist. v. 1: Butlin, St. Earth. Hosp. Rep. 

 1879,37. 



TONGUE OF MOLLUSCA. The tongue, 

 odontophore, or palate of the Mollusca, has 

 long formed an interesting microscopic ob- 

 ject on account of the elegant horny or 

 chitinous teeth situated upon it, in nu- 

 merous rows and in various patterns. 



The tongue forms a shorter or longer 

 ribbon-like structure, attached behind to the 

 bottom of a sac or sheath, situated on the 

 lower wall of the pharynx. It is supported 

 by a cartilaginous cushion, over which it 

 works backwards and forwards by muscular 

 action. 



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