297—120 INDIAN TERTIARY AND POST-TERTIARY VERTEBRATA. 
mandibles referred to II. felina. The crocutine type of the carnassial renders it 
pretty certain that the former mandibles should be referred to a species in which the 
upper carnassial was also of the crocutine type : in this respect, therefore, they 
might well belong to the same species as the skulls and upper jaws described above. 
The more slender form of the mandibles, the smaller size of the diastema, the 
relatively larger m. 1, and above all the internal position of the anterior vertical 
ridge of pm. 4, and the relatively taller crowns of this and the preceding tooth, are, 
moreover, all characters in which the lower jaws of the skulls described above would 
be expected to differ from those of E. felina ; and there is, accordingly, every 
probability that the mandibles under consideration belong to the same species as the 
skulls and upper jaws. 
Comparisons . — Assuming all these remains to be rightly associated, the species 
to which they belong will be characterized by having its skull and mandible 
somewhat more slender than those of II. felina ; by having carnassials more nearly 
of the crocutine type ; by the upper true molar being tricuspidate, and transversely 
elongated, though varying considerably in size ; b}^ (as far as is known) the absence 
of p m. 1, and the smaller length of the diastema in both jaws ; by the tall curved 
crowns of the conical premolars, the inward position of the anterior vertical ridge 
in pm. 3 and pm74, and the small size of the anterior talon of the latter. The species 
agrees with typical hyaenas in the absence of pm. 1 and m. 2. 
The distinctions between the specimens thus grouped together from the 
corresponding parts of H. felina have been already sufficiently indicated in the 
course of the foregoing descriptions, and are of such importance as apparently to 
preclude the possibility of uniting the two forms under one species. The points 
distinguishing the specimens under consideration from II. felina , will have the same 
value in the case of H. sinensis. 
In regard to its dentition generally, the present species makes in many respects 
a very strong approach to H. crocata , especially in the characters of the premolars 
and carnassials: it is, however, distinguished by the tricuspidate character and 
generally larger size of m. 1 ; the absence (as far as is known) of pm. 1 ; the smaller 
size of the diastema ; the larger talon and more distinct outer cingulum of m. 1 ; 
and the generally more pronounced character of the inner vertical ridges and 
‘ triangle ’ of pm. 3 , and the oblique setting of this and the preceding tooth. The 
third lobe of pm. 4 is generally smaller, and the width across the tubercle less, but in 
one instance the third lobe is as long as in H. crocuta. The hind talons of pm. 3 and 
pm. 4 are, moreover, relatively smaller ; while the ridge on the inner side of the 
hind talon of the latter tooth is less developed, and does not extend internally to the 
main lobe. The skulls of the two also differ considerably, the Siwalik specimens 
being smaller and more slender. The mandible of the latter is also more slender 
and straighter interiorly, lacking the great increase in depth below m. 1, which 
forms such a marked feature in II. crocuta. 
II. antiqua is too imperfectly known to admit of accurate comparisons. Of the 
