220 ELEMENTS OF MAMMALIAN ANATOMY. 
is known as the Schneiderian membrane. Ina fresh speci- 
men it is of a grayish color while the other mucous mem- 
brane is red. The first pair of cranial nerves convey the 
olfactory impulse to the brain. They pass through the fora- 
mina in the cribriform plate of the ethmoid bone, to the 
olfactory bulbs, from each of which two roots extend to the 
base of the cerebrum (Fig. 93). : 
The Gustatory Organ.—The organ of taste is located 
chiefly in the mucous membrane on the dorsum of the 
tongue, the soft palate, the pillars of the fauces, epiglottis, 
and part of the cheek. On the dorsum of the tongue are 
seen four kinds of papille—the circumvallate, the fungi- 
form, the filiform, and flat. The circumvallate papille are 
from eight to twelve in number, forming two sides of a 
triangle on the caudal portion of the dorsum of the tongue. 
The fungiform are blunt papillz scattered sparsely in the 
midst of the numerous filiform or pointed papillae (Fig. 56). 
The special organs of taste, known as taste-buds, are very 
numerous in the fungiform and circumvallate papille of 
most mammals, but in the cat they are few and not well 
differentiated. These tastebuds occur in many parts of the 
mucous membrane of the mouth cavity, each being supplied 
with a branch of the glossopharyngeal nerve. 
The Visual Organ.—The special organ of sight is the 
eye, which occupies the orbital cavity of the skull. The ball 
of the eye is protected above and below by extensions of 
skin called the eyelids or palpebre, which are lined with 
mucous membrane, a transparent layer of which, known as 
the conjunctiva, extends over the front of the eyeball be- 
tween the two lids. The dorsal lid is raised by the levator 
palpebre muscle, which has its origin in the occipitofrontalis 
muscle. <A sphincter muscle, the orbicularis palpebrarum, 
lies on the margin of the lids, and by its contraction closes 
the eye. 
