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THE CANINES OB CUSPIDS. 31

mesio-distally and in beinfr flattened in the neck and root. The crown
leans backward on the root so that the mesial face is almost straight the
entire length of root and crown. It forms the spring of the lower arch,
and is strongly built to oppose the strong upper canine in the act of
prehension and tearing. It opposes the mesial surface of the canine
above and the distal surface of the upper lateral incisor.

The lower canine.
The labialface is a long oval (a), the cusp being blunt and the neck
rounded while the mesial side (e) is flattened. The lobes are indistinct
and the central ridge rounded from side to side. The entire face is in-
clined inward to accommodate the occlusion. The crown in many cases
presents the appearance of being blunt toward the distal side.
The lingual face (6) is flat, sometimes cup-shaped, and the marginal
ridges are not prominent. The central ridge sometimes stands out
strongly. The basal ridge is weak and is rarely developed into a
cingule. The crown increases gradually in thickness from the point
to the neck.
The iiwrsal surface presents a mere rounded eminence ; the cusp may
be sharp in childhood, but usually it is soon reduced by wear. Some-
times it remains sharp and prominent. The lateral edges are not devel-
oped, but are mere ridges leading down to the lateral faces, which are
not prominent, except the distal {«1), which is often full.
The mesialface is quite flat, and straight with that face of the root.
The eminence is not marked. It is rounded only at the eminence, but
flattened at the cervical third (c).
The distal face has the most prominent eminence (r/), the crown being
bent in that direction. The cervical third of this face is flat. It descends
rapidly from the eminence.
The neck is usually oval (/) or, when compressed, spindle-shaped
upon section {g), being depressed on the mesial and distal sides at the
origin of the grooves running up on the root. The enamel line is
not so variable as on the incisor, but more nearly on a level on all four
aspects.