339—162 INDIAN TERTIARY AND POST-TERTIARY YERTEBRATA. 
behind which there is the alveolus of the milk-tubercular ( mm. 4). 1 The portion of 
the canine still remaining is serrated on its posterior edge, and laterally compressed, 
with the inner surface flat, and the outer convex : when complete it must have been 
relatively large, and considerably curved. The alveolus of mm. 4 is relatively large, 
as in the cubs of Felis. The milk-carnassial is almost an exact replica in miniature 
of the permanent carnassial of M. sivalensis ; with the exception of the almost total 
disappearance of the internal tubercle. From this fact, and the circumstance that 
the relative proportions of mm. 3 and pm. 4 in this specimen and the adult maxilla of 
M. sivalensis , are the same as those existing between mm. 3 and pm. 4 in Felis tigris , it 
may be taken as certain that the present specimen belongs to the former species. 
Canine. — In figure 6 of plate XLIV. there is represented the lower part of a 
tooth, 2 collected by Mr. Theobald in the Siwaliks of the Punjab, which there is every 
reason to believe is the permanent right upper canine of the present species. The 
tip of this tooth has been broken off ; and the whole crown is so rolled that any 
serration of its edges that may have existed has disappeared. The crown is laterally 
compressed, with the inner surface flat, and the outer convex : the anterior border is 
strongly convex, and the posterior concave. On the latter border there is a well- 
marked groove, externally to the trenchant edge, which disappears towards the 
extremity of the tooth. As this tooth is precisely similar in form to the milk- 
carnassial of M. sivalensis, it may be referred to the same species. 
In its degree of curvature this tooth is not unlike the upper canine of M. 
latidens , 3 but the crown was probably longer. In no species is the inner surface so 
perfectly flat as in the Siwalik tooth ; M. neogceus apparently coming nearest in this 
respect. The groove on the posterior border seems to be peculiar to the Siwalik 
tooth. The antero-posterior diameter of the latter at the point of fracture is 0’83, 
and the transverse O’ 5 inch. 
Cranium . — In the Indian Museum there is a specimen of the hinder portion of 
the cranium of a carnivore, collected by Mr. Theobald in the Siwaliks of the 
Hushiarpur district, which from the elongated form of the mastoid process evidently 
belongs to Machcerodus ; and from its size may probably be referred to the present 
species. The specimen is so imperfect and so damaged, that it has been considered 
advisable to figure it only on a reduced scale (fig. 20). The occipital crest is more 
developed than in any non-Indian species, M. neogceus coming nearest in this respect ; 
the posterior portion of the sagittal crest bending upwards very rapidly. The 
mastoid process of the periotic (mf is much produced interiorly, and indicates the 
1 In his original description (“ Brit. Foss. Mamm. and Birds," p. 178) Prof. Owen thought there was the alveolus of a 
small tooth between the canine and mm . 3. Dr. Falconer and Mr. Bose have, however, shown that this is not the case. 
2 The section of this tooth exhibits a thick coating of enamel, leaving no doubt as to its mammalian nature. 
3 “ Brit. Foss. Mamm. and Birds,” fig. 69, p. 180. 
4 In describing the American machserodonts Prof. Cope (‘ Amer. Nat vol. XIV, p. 854) applies the term ‘ post- 
tympanic process ’ to the whole of the bony pedicle situated behind the lower part of the auditory meatus (woodcut, fig. 20, 
»*) : a comparison of his figures, and of Blainville's plate of M. neogceus (“ Osleographie ,” Felis, pi. XX.), with the skull of 
the tiger, shows, however, that this part corresponds -in the main to the mastoid process of the periotic, although it is quite 
probable -that a thin post-tympanic process of the squamosal may he applied to its anterior surface. The process will 
accordingly here he termed the mastoid. 
