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OF THE CUSPIDATUS. 73
conceived, by supposing an Incisor, with its comers rubbed off',

structural differences between Man and those forms of life which ana-
tomically approach him nearest.
In its conical shape, the human cuspidatus does not present an ex-
ception to the configuration of canine teeth generally ; but its peculiar
characteristics are its small, absolute, and relative size, and the
absence of any difference in its development in the two sexes. It is
more deeply implanted, and possesses a stronger fang than the incisors ;
flat, or sub-concave, and
its external surface is convex, its internal is
presents a slight prominence at its base. In the genus Troglodytes, the
canine tooth in both sexes is of greater relative size than in the human
subject, but in the male sex it attains vastly superior dimensions. In
the adult male of both Tr. Gorilla and Tr. Niger, the apex of the
upper cuspidatus extends a little below the alveolar border of the lower
jaw when the mouth is shut : in the female the apex is lodged in the
interval between the lower canine and first premolar. The crown of the
upper laniary in the male is pointed, and of a conical figure ; its ex-
ternal surface is convex, presenting a longitudinal depression ante-
is somewhat flatter, and is bounded by a sharp
riorly ; posteriorly, it
cutting edge ; the internal surface is divided into an anterior and pos-
terior facet by a longitudinal rising ; the posterior is concave, and both
it and the anterior are grooved longitudinally. In the male Gorilla the
cuspidatus has a more outward direction than in the Chimpanzee ; the
anterior internal groove is deeper, and the internal ridge is more
developed ; the posterior internal groove is continued lower on the
fang, and the posterior trenchant edge is more produced towards the
The size of the canine in the male Gorilla is greater, as compared
base.
with the incisors, than in the Chimpanzee ; in the male of both species,
it attains twice the size of the same tooth in the female. In length the
enamelled crown of the superior canine in the adult male Tr. Gorilla,
measures one inch and four lines. An equal sexual distinction is main-
tained in the dimensions of the canines in the lower jaw. The crown
of the lower canine is conical and trihedral, its external surface is con-
vex, and the two internal are flat or slightly concave, and converge to
an almost trenchant edge. Anteriorly, a ridge separates the external
from the antero-internal surface. The entire length of the lower canine
in the male Gorilla, is two inches and a half ; in the Chimpanzee, two
inches. The crown in the larger species is one inch and a quarter in
length, and nearly an inch in breadth at its base ; in Tr. Niger, it is
three-quarters of an inch in length, and two-thirds of an inch across
the base. In the Orangs (PitJiecus), a like high degree of development
is attained by the canines, which present the same sexual difference,
and the same general configuration. The laniary of the Great Orang
does not, however, quite equal that of the Gorilla, either in Length or
breadth. The posterior trenchant margin of the upper tooth is mode-