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TEETH OF THE VERTEBRATA. 455

tion, as almost all evidence of palaeontology goes to show. The teeth
are not otherwise remarkable, resembling distantly those of the dog in
general pattern. The sectorials are not well defined, and the crowns
generally have a tendency to the tubercular structure.
The second division of the Fissipedia (^Ailuroidea) includes five fam-
ilies, the exact definitions of which the increasing knowledge of the
extinct forms is tending every
Fig. 233.
day to break down into hopeless
confusion. The definitions are
already very unsatisfactory and
in many cases fiiil to define.
The families which approach
nearest to the Canklce are the
Hycenidce or hysenas, and the
Viverridce or civets. The evi- Superior Dental Series of IcIUherhnn robiixfuni, two-
thirds natural size (from Cope, alter Oaudry).
dence already cited brings the
former of these families into the closest relationship with the central
cynoid group. The dental formula of the existing hyaenas (Fig. 234)
is, I. f , C. \, Pm. ^, M. \ = 34. The incisors and canines have very
much the same pattern as the corresponding teeth in the dog, as do
also the premolars, with the exception of their more robust proportions
Fig. 234.

Skull of Striped Hyrena, Ifycena striata.
and the addition of an anterior cutting lobe to the superior sectorial.
In the lower sectorial the heel is very rudimental and the internal
tubercle is wanting. The single superior true molar is small and