156 INTESTINAL MUCOUS MEMBRANE. 



as those of the cutis, and presenting a structure, 

 which, though perhaps a little more delicate, contains 

 the same elements. There is a striking analogy also 

 in the distribution of its vessels and nerves, but up to. 

 the present time no tactile corpuscles have been 

 observed, except in the papillae of the lips. On the 

 hard palate and the gums the mucous layer is strongly 

 adherent to the periosteum, with which, in fact, it is 

 continuous ; but on the cheeks and lips, it is rein- 

 forced by a delicate fibrous layer, by which it is 

 loosely connected with the subjacent muscles. 

 Epithelium. Its epithelial investment presents the same general 

 physiognomy as the epidermis ; the two deeper strata, 

 corresponding to the rete mucosum of the cuticle, are 

 absolutely identical with it, both in the shape of their 

 cells, and in the order of their superposition. The 

 superficial layer is likewise composed of scaly cells, 

 but differing from those of the skin in the persistence 

 of their nuclei. 



Glands. The glands of this portion of the alimentary mu- 

 cous membrane are all of the clustered variety ; they 

 occupy the sub-mucous stratum, sometimes even, as in 

 the cheeks, being imbedded in the muscular layer ; on 

 the hard palate and gums they are absent. 

 MUCOUS mem- The mucous coat of the inferior surface of the 



brane of the 



tongue is similar to that of the lips, but on its dorsal 

 aspect it is very different, both in its external appear- 

 ance, and in certain structural details. 



On the base of the organ its mucous membrane is 

 almost smooth, and sparsely studded with little len- 

 ticular prominences, with a hole in the centre of each, 

 formed by the projection of small masses of subjacent 



