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58 HUNTER ON THE TEETH.
The Teeth differ very much in figure from one another ; but
those on the right side in each Jaw resemble exactly those on
the left, so as to be in pairs ; and the pairs belonging to the
Upper-Jaw nearly resemble the corresponding Teeth of the
Lower-Jaw in situation, figure, and use.
Each Tooth is divided into two parts, viz., first, the body, or
that part of it which is the thickest, and stands bare beyond
the Alveoli and Gums ; secondly, the fang, or root, which is
lodged within the Gum and Alveolar Process : and the boundary
between these two parts, which is grasped by the edge of the
Gum, is called the Neck of a Tooth. The bodies of the different
Teeth differ very much in shape and size, and so do their roots.
The difference must be considered hereafter.
The Teeth of each Jaw are commonly divided into three
classes, viz. Incisors, Canine, and Grinders ; but from consi-
dering some circumstances of their form, growth and use, I
chuse to divide them into the four following classes, viz. Inci-

It occasionally happens that the last molars, or wisdom teeth, remain
enclosed in their bony recesses until a late period of life. In some few-
instances they may be absent.
In the class Mammalia, examples of the greatest number of teeth are
observed amongst those forms which generate but a single set of teeth
Thus the
{Monophyodonts), and occur in the orders Cetaceaand Bruta.
priodont Armadillo has ninety-eight teeth ; the Cachalot, u] twards i if sixty,
most of them being confined to the lower jaw ; the common Porpoise
has between eighty and ninety ; the Gangetic Dolphin, one hundred
and twenty
; whilst the true Dolphin presents the maximum number in
Mammalia, having from one hundred to one hundred and ninety teeth.
Where the teeth are excessive in number, they are of small size, equal or
nearly so, and usually conical in form.
In placental Mammalia which have two sets of teeth the one succeed-
ing the other (Diphyodonts), the number of the permanent teeth never
exceeds forty-four.
A few genera and species of Mammalia are strictly edentulous. Thus
the true Ant-eaters (Myrmecophaga), the scaly Ant-eaters (Manis), and
the spiny monotrematous Ant-eaters (Echidna) possess no true teeth,
although in Echidna homy processes are present analogous
to the
lingual and palatal teeth in fishes.
(1)]
(1) Owen, op. cit., pp. 5— 9, and Art. Odontology, Enc. Brit., 8th edit.,
438.