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80 HUNTER ON THE TEETH.

perpendicularly, but seem to be a little turned inwards, especially
the last of them.
In the Upper-Jaw they are rather thicker than in the Lower,
and are turned a very little forwards and outwards.
The first in
The second
the Upper-Jaw falls between the two in the Lower.
falls between the second and the first Grinder
: and both project
over those of the Lower-Jaw, but less than the Incisores and
Cuspidati. (m)
The Bicuspides, and especially the second of them, in both
Jaws, are oftener naturally wanting than any of the Teeth,
except the Denies Sapientice; thence we might conjecture that
they are less useful; and this conjecture appears less impro-
bable, when we consider, that in their use they are of a middle
nature between Cutters and Grinders; and that in most animals,
so far as I have observed, there is a vacant space between the
Cutters and Grinders, (n) I have also seen a Jaw in which the
(m) [The premolars present no variation in configuration in the
different varieties of Man. Like the molars, as a rule, they are of large
; although, even
size in the Melanian races, especially in the Australian
among these, exceptions occur in which these teeth are not of greater
dimensions than in some individuals of other races.
(n) In many instances in which the second bicuspid (p. 4) appears to be
absent, it is prevented comiug into place by the retention of the second
deciduous molar to a late period of life. The retention of the first decid-
uous molar may, in like manner, prevent the appearance of the first bicus-
pid. It would appear, however, that this is more rare. It occasionally
also happens that the second bicuspis is altogether ivndeveloped, in which
case the second deciduous molar permanently supplies its place. Mr.
Tomes states that, according to his experience, the lateral incisors are
more frequently absent than any other teeth, with, perhaps, the exception
of the wisdom. (1) Comparative anatomy does not warrant us in seeking
any analogy between the occasional absence of the second bicuspis in
Man, and the existence of a diastema between the grinders and cutters
in the lower animals, for the second bicuspis is the homologue of the
tooth (p. 4), which of all the premolar series is most constant in placental
diphyodouts. The premolars in the higher Mammalian dentition form
part of the same series with the molars, in front of which is the diastema,
separating them from the canines and incisors ; and reduction in the
number of premolars always takes place by the suppression of one or
more of the anterior teeth.
(1) Tomes's System of Dental Surgerv. p. 221.