HYENA SPELZA. 139 
The four lower molars all belong to the spurious series, 
the last being the sectorial tooth. The upper jaw of the 
Hyena has five molars on each side, a small tubercular 
true molar terminating the series, which includes four, in- 
stead of three premolars as in the genus /e/is. 
The most characteristic modification in the dentition of 
the Hyena is the strong conical shape of the second and 
third premolars, in both upper and lower jaws, the base of 
the cone being belted by a strong ridge, which defends 
the subjacent gum.* This form of tooth is especially 
adapted for gnawing and breaking bones, and the whole 
cranium is modified by the enormous developement of the 
muscles which work the jaws and teeth in this operation. 
The tooth of the Hyzna most liable to be mistaken for 
one of a large Feline animal, is the sectorial or last molar 
Fig. 55. 
Nat. size, Kirkdale Cavern. 
of the lower jaw (jig. 55); it is distinguished by the 
presence of two small tubercles, one at each end of the base 
of the crown. 
* An eminent civil engineer, to whom I once showed the jaw of a Hyzna, 
said, that, if he wanted a model for the form of a hammer best adapted for break- 
ing stones for roads, he should take the strong, conical, ridged tooth of that 
animal, 
