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OF THE GRINDERS. 85
there divides into two flat fangs, one forwards, the other back-
wards, with their edges turned outwards and inwards, and their
sides consequently forwards and backwards : the fangs are but
very little narrower at their ends, which are pretty broad, and

of the molar teeth in the Elephant—together with the shape, structure
and implantation of these organs indicate a near approach to the
pachydermal type. The molars of the Dugong resemble in the double-
ridged character of the crowns those of the Tapir, Dinotherium, Dipro-
todon, and Kangaroo.
The typical number of the molar teeth in the Marsupial Order is
seven on each side of both jaws ; of which the three first succeed three
deciduous teeth, and are premolars, whilst the true molars are four in
number. In the Thylacine, there are three premolars and four molars on
each side, both above and below. The premolar has a simple compressed
conical crown, with a posterior tubercle, which is most developed in
the third. The crowns of the upper molars are of an irregularly
triangular figure. The outer part of the crown is raised into three
cusps, of which the middle is the largest, and from the inner side of the
crown projects a small, strong, obtuse lobe. The lower molars are
compressed and tricuspid ; the centre cusp being the longest, especially
in the third and fourth, which resemble closely the dents carnassie'res of
the Felidce. In the Dasyures, the premolars are reduced to %'. \\ ; the
molars are £ \ J \ . The premolars have simple crowns. The crowns of the
upper true molars are triangular ; the first has four sharp cusps ; the second
and third each five, whilst the fourth, which is smallest, is tricuspid.
The last lower molar is nearly of equal size with the third ; it presents
four cusps, of which the outer is the largest ; the second and third have
five cusps, three on the inner side, and two on the outer ; the first is
quadricuspid. An extinct carnivorous Australian Marsupial, to which
Professor Owen has given the name of Thylacoleo, had a true carnassial
tooth, upwards of an inch and a half in fore and aft extent, and one inch
in height. In the lower jaw, the crown of this tooth consists entirely
of blade ; in the upper, there is a feeble tubercle superadded. In the
smaller species of carnivorous Marsupials, the character of the molars
approaches the insectivorous type, in being more cuspidate than sec-
torial. This is the case in the Phascogah, in which the formula of the
molar series is p. & " %[ m £\ $[ . In Myrmecobius, with the same num-
. The molars in
ber of premolars, the true molars are increased to % \ %\
Myrmecobius are multicuspid ; they are separated from each other, as
are also the premolars, by short intervals ; both molars and premolars
are implanted by two fangs, an implantation general in the Marsupial
Order. The lower molars are directed obliquely inwards, so that their
outer surfaces come into contact with the working surfaces of the
upper. The premolar is compressed and triangular, with the apex
L