INTESTINAL MUCOUS MEMBRANE. 



ductless follicles. The rest of its dorsal surface is Ductless. 

 thickly covered with very prominent papillae, which 

 from their variety in form, are divided into three sets, 

 viz : circumvallate,fungiform, and conical, or filiform, 

 papillae. 



The papillae of the first set are found immediately 

 in front of the base of the tongue, where they are 

 arranged in the shape of the letter V. They have 

 the shape of an inverted cone, with the apex conti- 

 nuous with the membrane below, and its base looking 

 upwards and free, and are moreover surrounded by 

 an elevated circle formed by the mucous membrane, 

 which constitutes a sort of imperfect capsule, in 

 which they are almost concealed (PL XXV. fig. 

 III. 1). 



IL\\Q fungiform papillae have the same shape as the 

 last, but are smaller, and project farther from the 

 surface of the membrane. They are pretty uniformly 

 distributed over the whole surface of the tongue, 

 being somewhat more numerous at its border and 

 tip. 



The filiform papillae, whose shape is very well riiiform papiiiae. 

 indicated by their name, although found everywhere 

 on the upper surface of the tongue, are more nume- 

 rous in the neighborhood of its median line than its 

 edges, where they lose their characteristic appear- 

 ance (PL XXV. fig. IV.). Their direction is obliquely 

 upwards and backwards. 



Each papilla, whatever may be its shape, is com- structure, 

 posed of the mucous membrane proper, of the sub- 

 stance of which it is a projection, and covered 

 externally by epithelium. In each of the three 



