166 MICROSCOPIC AXATOMY OF THE ORGANS. 



The papillae vallatce or circumvallatce (Fig. 122) are so 

 named on account of being surrounded by a sort of trench. 

 They are about nine or ten in number in man, and are arranged 

 in two lines which diverge forward from the foramen caecum at 

 the back of the tongue. They thus form a V-shaped line, with 

 the apex behind and the arms forward. They resemble the 



FIG. 122. 



Fur rou~ around papilla -rjitSff^>' 



Epithe- 

 Hum 



Sub- 

 mucom 



Perpendicular section through a papilla vallata of the human tongue, a; a:, taste 



buds, x 37. 



papillae fungi formes somewhat in general form, but are consid- 

 erably larger than these, usually measuring 1-2 mm. in diam- 

 eter and 1 mm. in height. They are usually sunken in the 

 mucous membrane and surrounded by a groove and a wall. 

 The latter is somewhat lower than the papilla. Only the upper 

 surface possesses secondary papilla ; the side walls remain free 

 from them. The latter, however, show the end apparatus of 

 the nerves of taste, the so-called taste bulbs. These are some- 

 times found also in the wall on the opposite side of the trench. 

 Their intimate structure is described in the section on Sense 



