954 THE DIGESTIVE SYSTEM. 
The fungiform papille (Fig. 642) are larger and redder, but less numerous than 
the last variety, and they are found chiefly near the tip and margins of the tongue, 
comparatively few being present over the dorsum generally. . Kach is in shape like 
Eran ieli an ae a “puff-ball” fungus (Halliburton), 
Sans consisting of an enlarged rounded 
head, attached by a somewhat 
narrower base. As in the case of 
the conical papille, the corium 
is studded over with microscopic 
papille, which are buried in the 
covering of squamous epithelium 
and do not appear on the surface. 
Most of the fungiform papillee, if 
not all, appear to be furnished with 
taste-buds, and they are probably 
intimately connected with the sense 
of taste. 
The circumvallate papille 
(Fig. 642), by much the largest of 
all the papilla of the tongue, are 
confined to the region immediately 
in front of the sulcus terminalis 
and foramen cecum. Usually about 
serous ten in number, they are arranged 
standin the form of the letter V, with 
the apex backwards, just in front 
of and parallel to the sulcus ter- 
Conical papillze 
“a 
y 
Sta 
A circumvallate papilla. x12. 
minalis. One or two of the papillae 
Fic. 642.—THE PAPILLA OF TONGUE. are usually placed at the apex of 
The upper illustration shows conical and fungiform papille, the Vi immediately anterior to the 
the lower a circumvallate papilla. CC. Corium, and foramen cecum. In appearance a 
E. Epithelium of the mucous membrane. The wavy . : : 
dark lines represent arteries. circumvatllate papilla resembles very 
closely the impression left by press- 
ing the barrel of a small pen on soft wax (Fig. 641). Each is composed of a 
cylindrical central part (1 to 2°5 mm. wide), slightly tapering towards its base, and 
flattened on its crown, which projects a little above the general surface of the tongue. 
This is surrounded by a deep, narrow, circular trench or fossa, the outer wall of 
which is known as the vallum. The vallum appears in the form of an encircling 
collar very slightly raised above the adjacent surface (Fig. 640). 
As in the case of the other forms, the circumvallate papilla are made up of a 
central mass of corium, beset with numerous microscopic papille on the crowns, 
but not on the sides, and covered over, as are the surfaces of the fossa and vallum, 
by stratified squamous epithelium. Into the fossz open the ducts of some small 
serous glands (Fig. 642). 
On the sides of the circumvallate papillae, as well as upon the opposed surface 
of the vallum, are found, in considerable numbers, the structures known as taste 
buds, the special end-organs of the nerves of taste. 
The apex (apex linguze), and the margin (margo lateralis) of the tongue in 
front of the attachment of the anterior palatine arch, are free, and lie in contact 
with the teeth when the tongue is at rest. 
On the upper half or more of the margin and apex, papilla are present as on the dorsum ; 
but on the lower part they are absent, and the surface is covered by smooth mucous membrane. 
Just in front of the anterior palatine arch, on the margin, are usually seen about five or six 
distinct vertical folds, forming the folia lingua, which are beset with taste-buds, and correspond 
to a well-defined area (the papillee foliatee) on the side of the tongue in certain animals (rabbit, 
hare, ete.), in which it forms an important part of the organ of taste. 
The inferior surface (facies inferior) of the tongue, which is exposed by turning 
the apex of the organ upwards, is limited in extent (Fig. 645), and is free from 
visible papille, the surface being covered by a smooth mucous membrane. Running 
