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10 OF THE ARTICULATION OF THE LOWER-JAW,
eminence,
(q) placed in the same direction, convex upon the top,
in the direction of its shorter axis, which runs from behind for-
wards ; and a little concave in the direction of its longer axis,
which runs from within outwards. It is a little broader at its
outer extremity ; as the outer corresponding end of the Condyle
describes a larger circle in its motion than the inner. The
surface of the cavity, and eminence, is covered with one con-
tinued smooth cartilaginous crust, (r) which is somewhat liga-
mentous, for by putrefaction it peels off, like a membrane, with
the common Periosteum. Both the cavity and eminence serve
for the motion of the Condyle of the Lower-Jaw. The surface
of the cavity is directed downward ; that of the eminence down-
ward and backward, in such a manner that a transverse section
of both would represent the Italick letter S. Though the emi-

spects presents a curious association of the characters of the osseous
and cartilaginous fishes, the pterygoid hone contributes the inner, the
tympanic the outer portion of the recipient articular surface. (1)
The articulating portion of the glenoid cavity is hounded posteriorly
in the Anthropoid Apes, and generally in the lower Mammalia, by a
prominent ridge or process. In the Rodentia, a similar ridge bounds
the articulating cavity internally. In Man this posterior boundary is
absent, or but slightly indicated. The downward development of the
human cranium posterior to the articulating surface, affording, as it
does, a support against backward dislocation, obviates the necessity for
the development of a post-glenoid process. (2) When its rudiment
exists in Man, it is known as the middle root of the zygoma. I believe
that the Author of the article Temporo-Maxillary Articulation is mis-
taken when he asserts that this process is more frequently indicated in
the lower races of mankind. I have seen it at least as frequently in
the skulls of the natives of Europe and Asia as in African and Austra-
lian crania.]
(q) [Anterior root of the zygoma.]
(/•) [It is only that portion of the glenoid cavity concerned in the
articulation of the joint which is covered with cartilage.]

(1) Owen, Trans. Lin. Soc, vol. xviii., p. 336. Article Temporo-Maxillary
Articulation, in Todd's Cyclopaedia of Anatomy, by S. R. Pittard.
(2) Owen, Zool. Trans., vol. i., p. 340.