side, convex externally and concave internally. The root of the tooth curves hack
abruptly from the crown.
The second incisor partakes somewhat of the character of the canine in having
its anterior and posterior margins parallel for a certain length, and in the bevelling
off1 of the anterior to the posterior margin. Opposite to where this takes place,
there is a faint concavity on the posterior margin of the tooth. I t is also laterally
compressed and broadest from before backwards. I t is directed forwards and
downwards, and is shorter than the canine, which has a nearly similar but more
vertical course.
The first incisor is also broadest from before backwards with a similar curve,
combined with a divergence or outward curve of the tooth; so that when viewed
in front, its external margin is concave and its internal margin is convex. The
crown and root together of these incisor teeth form a considerable curve. They are
directed forwards and backwards.
The third deciduous premolar in the lower jaw resembles the molars in every
respect, only it is considerably smaller than the first. Internally it shows three cusps,
of which the central one has the greatest vertical length; and externally it is composed
of two large triangular cusps, the anterior of which, the most vertically elongated
of all, is connected to the two anterior of the internal cusps by a ridge running to the
anterior border of the foremost and to the posterior margin of the hindmost, enclosing
a triangular hollow. The cusps posterior to this are on a much lower level and
below all the upper cusps. Besides the external and internal cusps, there is another
which may be termed posterior, and which is behind and external to the last internal
cusp. I t is connected to the external cusp by a concave ridge, and it has little •
or no vertical extension. I t corresponds to the middle cusp of the internal series,
to which it rightly belongs. I t is separated from the hindmost internal cusp by
a deep notch; it has only two fangs corresponding to the two triangular surfaces
of the crown.
The second premolar (in lower jaw) is a bi-cuspidate tooth, consisting of one large
anterior sub-triangular cusp with a rather prominent talon at its base posteriorly.
The large cusp is concave posteriorly and convex anteriorly, where its upper surface
is bevelled off from before backwards, producing a rather prominent angle. The inner
surface is convex in the middle line, but grooved on either side of it. I t has two
divergent fangs which partially embrace the crown of the permanent tooth, but are
so external to it that it cannot be detected when the roots of the teeth are laid bare
from without. This tooth differs little from the permanent tooth, which is larger.
The first premolar (lower jaw) is laterally compressed, convex anteriorly and
concave posteriorly, in profile, the latter margin running nearly to the tip or point of
the crown of the tooth, from which it is separated by a short bevelled surface: the
point rounds off to the anterior margin. At the posterior margin, the angle formed
by the crown of the tooth and the single cylindrical tapering fang, corresponds to
the posterior talon of the second premolar. Its permanent tooth lies immediately
below its root.
The canine has the greatest vertical extension of all the teeth in the lower jaw,
and the deciduous tooth has a shorter and more obtuse crown than the permanent
tooth. I t is laterally compressed, and its posterior margin, viewing it in profile, has a
slight swelling near its base, corresponding to the talon of the second premolar, the
area or margin above it, to the point of the tooth, being concave. The anterior
margin is rounded forwards to the point, which is almost in the same line with the
posterior margin, and is directed forwards and upwards. The permanent tooth- lies
internal to it, resting upon the base of the fang, or nearly so.
The crown of the third incisor, as, to a certain extent, the crowns of the canine
and first premolar, is set on obtusely to the fang, the latter being directed downwards
and backwards, the former upwards and forwards to a greater degree than the
fang is in its course. The tooth is laterally compressed and its crown rounded; its
posterior margin convex from before backwards and almost straight; but where the
latter joins the fang an angular point is formed corresponding to the angle in the
canine and first premolar, and to the talon of the second premolar. Its permanent
tooth is very difficult to demonstrate; but I believe I have detected it lying at its
base externally, on the same plane as itself. On the internal aspect of the jaw the
young permanent canine and second incisor are so close, and the latter is placed so
obliquely from behind forwards, that there is no room for it in that direction, and
it has therefore to be sought for by removing the bone from the outer surface of
the jaw.
The second incisor has its anterior or external surface somewhat convex from
behind forwards with its lateral margins parallel and abruptly rounded off to the points.
The internal surface, concave from before backwards, has a convex longitudinal ridge
with a well-marked groove in the same direction external to it, and a more indistinct
one internally. The base of the crown forms an angular prominence externally with
the fang, from the circumstance that the crown is placed slightly obtusely to the root
of the tooth. The fang is long and reaches back to nearly on a line with the
posterior border of the symphysis. The permanent tooth lies internal to it, and
above, it is separated from the permanent first incisor by a longitudinal, or nearly
longitudinal, osseous ridge; it is chiefly distinguished from the deciduous tooth by
its larger size.
The first deciduous incisor is a narrower and more pointed tooth than the pre-»
vious one, but of the same structure, and is distinguished from its permanent tooth,
which lies internal to and resting on it, by its greater size.1
1 The specimen with abnormal dentition was received from Darjeeling, and is an example of T. belangeri. I t is
young, and on laying bare tbe roots o f the teeth of the upper jaw, I have been able to demonstrate which are the
superfluous teeth. None o f the permanent teeth,, except the three molars, are through the gum. As the dentition is
different in the two sides, I shall describe them separately. On the right side, above, there are ten teeth, the abnormal
tooth being small, partaking of the character of a diminutive canine wedged in between the deciduous canine and the
deciduous first premolar. The young permanent teeth are in their positions in front and at the base o f their respective
teeth, but no young tooth exists to take the place of the superfluous one. On the left side no less than eleven teeth occur,
one anterior to the canine and one behind it. These teeth are placed at equal distances from each other and are of equal
size, and all resemble diminutive canines. The middle tooth is the true canine, as is shown by the presence of the young
permanent tooth in front of it. The abnormal teeth on either side o f the canine are not represented by any young
tooth, so that the normal dentition would be attained in the adult state.