496 ORGANS OF DIGESTION. 



cular fibres are occasionally seen in this tissue in the human 

 subject : in the black bear of North America, and in some 

 other animals, it consists in a pair of strong muscles. The 

 pouch, on each side, is bordered, externally, by a more super- 

 ficial doubling of the mucous membrane, which passes, from 

 the base of the tongue to the side of the epiglottis.* 



The lingual portion of the lining membrane of the mouth, on 

 the upper surface of the tongue, is somewhat cartilaginous, and 

 into it is inserted many of the subjacent muscular fibres. At 

 the base of the tongue this cartilaginous condition is deficient, 

 and its place is supplied by a yellow cellular tissue which ad- 

 heres to the os hyoides, to the epiglottis, and to many muscular 

 fibres below, and has in it numerous mucous follicles. 



As observed, the mucous membrane, on the under surface of 

 the tongue, offers no peculiarity of organization : but, on the up- 

 per surface, it is remarkable for the unusual size and develop- 

 ment of its papillae, for having its epidermis easily detached, and 

 also for having the muscular structure beneath fixed to it with 

 extreme closeness. 



The anterior two-thirds of the upper surface of the tongue 

 are entirely covered by these papilla. They are so thickly 

 set as to touch one another ; and, as they present some pecu- 

 liarities of form, they are divided into Papillae Maximae or Ca- 

 pitata?, Media?, Villosae, and Filiformes. 



The Papillae Maximae constitute the posterior border of the pa- 

 pillary surface of the tongue, and are about nine in number, 

 though they are frequently fewer, and sometimes more. They 

 are disposed in two oblique rows, which, by converging back- 

 wards, meet and generally form something like the letter V. ; the 

 fifth papilla being the angle of the figure. Each of these bodies 

 resembles a cone standing upon its summit, and is surrounded by 

 a circular fossa which permits it to project but inconsiderably 

 above the general level of the tongue. Sometimes two or more 

 are in the same fossa. The Papilla? Mediae, or Fungiformes, are 

 more numerous than the last, and next to them in size; they 

 are enlarged at their loose end into a sort of rounded head, 

 whence their name; they are irregularly scattered over the 



* This doubling also exhibits, occasionally, a small muscle inserted into its base, 

 and arising from the upper constrictor of the pharynx, and which has the 

 effect of widening the pouch. 



