ascending upon the fore as well as the back part of the strong
rounded cone : the third premolar (p 4) is proportionally less in
the Hyena crocuta than in the H. vulgaris-, its posterior ridge is
developed into a small cone. The last tooth (ml) is the sectorial
and consists almost entirely of a blade divided by a vertical fissure
into two sub-equal compressed pointed lobes : the points are less
produced than in the Felines, but the lower sectorial of the Hyaena
is better distinguished by the small posterior basal talon, from which
a ridge is continued along the inner side of the base, and is slightly
thickened at the fore-part of the crown. According to the relative
position of the crowns of the premolars, the third below ought to
be the last, being analogous to the fourth in the Viverride, and
the sectorial should be the first true molar: we shall find this view
confirmed by the test of the mode of succession of the permanent
teeth. But the mode of implantation of the premolar and molar
teeth may first be noticed. The first upper premolar has but one
fang; the second and third have each two; the sectorial tooth has
three, the two anterior ones on the same transverse line, the inner
one supporting the tubercle. The lower premolars and sectorial
have each two fangs, there being none truly answering to the first
above: the anterior root of the lower sectorial tooth is very strongly
developed in the great extinct Cave-Hyaena.
The deciduous teeth approximate, as usual, to the typical
dentition of the Carnivora; they consist of:—
Incisors — ; canines BH molars H " S 9 22.
The figure of the skull of the young Hyena crocuta in the posthumous
Edition of the ‘ Ossemens Fossiles,’ 8vo. 1836, pi. 190, fig. 3,
shows that stage when the correspondence with the formula of the
genus Felis is completed by the appearance, in the upper jaw, of
a small premolar in the interspace between the canine and first
molar of the deciduous series : but this appearance is due to the
apex of the first permanent premolar which cuts the gum before
any of the normal deciduous teeth are shed : whether it is preceded,
as in the Dog, by a deciduous germ-tooth in the foetus I
know not. The first normal deciduous molar is two-fanged, and
has a more compressed and consequently more carnivorous crown
than that of the second permanent premolar by which it is succeeded.
The second deciduous molar is the sectorial tooth: the
inner tubercle is continued from the base of the middle lobe, and
thus resembles the permanent sectorial of the Glutton (Gulo) and
many other Mustelide; the deciduous tubercular molar is relatively
larger than in the adult Hyena, and offers another feature of resemblance
to the permanent dentition of the Glutton. It is also
worthy of remark that the exterior incisor of the upper jaw is not
only absolutely, but relatively smaller in the immature than in
the adult dentition of the Hyaena, giving another feature of resemblance
to the more common type of dentition in the Carnivora.
The first and second deciduous molars below (PI. 126, fig. 9)
have more compressed conical crowns than their successors : the third
deciduous molar (fig. 9, 3) is the sectorial tooth, and, again, as in
Gulo, has a better developed hinder tubercle than the permanent sectorial;
it is not displaced by this tooth, but, as in other Carnivora,
by a premolar (p. 4) of more simple character. The permanent
sectorial (ml ) is developed posteriorly and rises, like
other true molars, without displacing a deciduous predecessor.
The permanent dentition of the Hyena, as of other genera or
families of the Carnivora, assumes those characteristics which
adapt it for the peculiar food and habits of the adult and mark
the deviation from the common type, which always accompanies
the progress to maturity. The most characteristic modification of
this dentition is the great size and strength of the molars as
compared with the canines, and more especially the thick and
strong conical crowns of the second and third premolars in both
jaws, the base of the cone being belted by a strong ridge which
defends the subjacent gum.(l) This form of tooth is especially
adapted for gnawing and breaking bones, and the whole cranium
has its shape modified by the enormous development of the muscles
which work the jaws and teeth in this operation. (2) Adapted
(1) An eminent Civil-Engineer, to whom I showed the jaw of a Hyaena, observed that
the strong conical tooth, with its basal ridge was a perfect model of a hammer for
breaking stones for roads.
(2) “ The strength of the Hyaena’s jaw is such that, in attacking a Dog, he begins
by biting off his leg at a single snap.” Buckland, ‘ Reliquiae Diluvianae,’ p. 23.