ies, extending from the nose to the pharynx. These cavities are
bounded superiorly by the sphenoid and ethmoid bones; inferiorly, by
the hard palate. In the middle line they are separated from each other
by a bony and fibro-cartilaginous septum; upon the outer wall of each
fossa, in the dried skull, are three projecting processes, termed
spongy bones. In the fresh fossa, these are covered by a mucous
membrane.

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876. Where is the sense of smell located? 877-884. _Give the anatomy
of the organs of smell._ 877. Name the parts that enter into the
structure of the nose? 878. What bones form the framework of the nose?
879. What is the use of the cartilages? 880. What relation has the
mucous membrane with other membranes of the nose? 881. Describe the
nasal cavities.

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882. The space that intervenes between the superior and middle spongy
bone, is called the _superior me-a'tus_, or channel; the space between
the middle and inferior bone, is the _middle meatus_; and that between
the inferior bone and the floor of the fossa, is the _inferior
meatus_.

[Illustration: Fig. 135. A vertical section of the middle part of the
nasal cavities. 7, The middle spongy bones. 8, The superior part of the
nasal cavities. 10, The inferior spongy bones. 11, The vomer. 12, The
upper jaw. 13. The middle channel of the nose. 14, The lower channel of
the nose. 17, The palatine process of the upper jaw-bone. 18, The roof of
the mouth covered by mucous membrane. 19, A section of this membrane.]

883. The MEATUSES are passages that extend backward, from the
nostrils, into which are several openings. They are lined by a mucous
membrane, called the _pi-tu'i-ta-ry_, or _schneiderian_, from
Schneider, who first showed that the secretion of the nasal fossae
proceeded from the mucous membrane, and not from the brain.

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882. What terms are applied to the spaces between these processes?
What does fig. 135 represent? 883. Define the meatuses. By what are
they lined?

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884. Upon the mucous membrane of the nasal passages, the olfactory
nerve ramifies, and also a branch of the fifth pair of nerves. This
membrane is of considerable extent in man; and in those animals whose
sense of smell is very acute, it is still more extensive.

[Illustration: Fig. 136. A side view of the passage of the nostrils, and
the distribution of the olfactory nerve. 4