SIWALIK AND NARBADA CARNIVORA. 
121—298 
species mentioned in the list on pp. 276-7 not already alluded to, II. perrieri , if 
distinct from H. crocuta, seems to approach the present species by the rather larger 
size of ml and the larger talon of mTl : it is, however, probable that in other points 
it is distinguished by the same characters as H. crocuta. II. eximia is sufficiently 
distinguished by the presence of pm. 1 and the small size of the inner tubercle of 
pm- 4 : and it is probable that in R. brevirostris similar differences prevail : the 
premolars of these species are of quite a distinct type from those of the present 
species. In H. grceca both pm. 1 and mT2 'are present, and the talon of mTl is 
relatively large. In all the other species the carnassials are of quite a distinct 
type to those of the specimens under consideration. As it will be shown below that 
these specimens are totally distinct from H. sivalensis of Mr. Bose, and as they 
cannot be identified with any other sufficiently described species, it appears that 
they belong to a new species, for which the name H. colvini is proposed, in honour 
of Col. Colvin, the discoverer of the two skulls described above, and numerous 
other Siwalik fossils. 
This species appears entirely to do away with the generic distinctness of 
Crocuta , since while its premolars and lower carnassial are of the type of the spotted 
hyaena, (although pm. 4 indicates a tendency to a transition from the crocutine to the 
striatine type), its upper true molar, in its different variations, forms an almost 
complete transition from that of the striped to that of the spotted species, though 
generally of the type of the former. Although H. colvini is in these respects 
intermediate between II. felina and II. crocuta on the one hand, and II. striata and 
II. brunnea on the other, yet if the absence of pm. 1 be constant (and it is in any 
case very frequent) the former species must be regarded as a highly specialized 
member of the genus, and cannot have been the direct ancestor of any of the living 
forms. The combined evidence of this species, of II. crocuta , and II. felina seems to 
indicate that in those species which attained a high degree of specialization in the 
structure of their carnassial teeth — i.e., an approach in the structure of those teeth 
to the homologous teeth of the modern cats — the concomitant reduction in the other 
teeth which usually occurs in such cases, took place either in the diminution of m. 1 5 
or in the suppressson of pm. 1 , or in a combination of both these characters. 
Distribution . — The present species ranged from the region of the typical Siwalik 
Hills to the Punjab. 
Species 3 : Hyaena macrostoma, n. sp. nobis. 
History . — The name of this species is mentioned here for the first time. 
Cranium .■ — In plate XXXVII. there are given two views of the cranium of a 
Siwalik hyaena collected by Mr. Theobald at Jabi, Punjab ; while a reduced profile 
view of the same specimen is given in fig. 2 of the preceding plate. The specimen 
comprehends the whole of the skull, and is in excellent preservation. It has, 
however, lost both zygomatic arches, the occipital condyles, and a part of the 
sagittal crest. The incisors and canines have fallen out from their sockets, and the 
d 2 
