315—138 INDIAN TERTIARY AND POST-TERTIARY VERTEBRATA. 
one lower incisor, and the enormous development of the descending mandibular 
expansion : in the presence of a talon to m. 1 it retains, however, evidence of its affinity 
to the more generalized cats, which is lost in the other machserodonts. In Machcerodus 
the inner tubercle of pm. 4 is always less developed than in Felis ; and in some cases 
may be almost or entirely absent : when present it is situated farther back than in the 
latter. The upper canines are distinguished from those of Felis, by their compressed 
form, serrated edges, and the absence of the vertical grooves which almost always 
occur in the latter. The outer upper incisor has serrated edges in some instances. 
It must be understood that it is impossible to arrange the Felidae strictly in one 
lineal series ; since it is pretty certain that the cheetahs, true cats, and machaerodonts 
form three diverging branches from the primitive stock. Even, however, in the face 
of this impossibility, the genera, as arranged above, exhibit on the whole a 
progressive advance in the structure of the carnassials ; and in the diminution in 
number of the premolars and lower molars. The presence of a talon and inner cusp 
to m. 1 in many of the lower forms, and the absence of a first lobe to pm. 4 are 
characters connecting the family with the Viverridce , and possibly (if the musteline 
affinities of Procelurus and Steneoplesictis are rightly determined) with the Mustelidce. 
As it is certain that the higher species did not descend from the lower cats through 
the intervention of the hyaenas, 1 it is clear that the development of the first lobe of 
pm- 4 in Felis is another instance of the separate origin of this part. 
In the otherwise generalized genus Cyncelurus , as well as in Machcerodus and 
Mlurodon the specialization of pm. 4 , by the abortion of its inner tubercle, is 
analogous to the condition prevailing in Icticyon among the dogs. 
Although the number of lower teeth in Felis is generally very constant, yet the 
present writer has recorded 2 one instance of the presence of pm. 2 in F. tigris , while 
De Blainville 3 has figured a lower jaw of F. lynx in which m. 2 is present. Both 
these instances are probably to be regarded in the light of reversions ; and the 
second instance is very noteworthy, since the lynx in the retention of a rudiment of 
the talon of m. 1 exhibits a connection with the primitive feline stock more clearly 
than any other existing cats 4 ; the cheetah ( Cyncelurus ) coming next in this respect. 
In describing the Indian fossil remains of the family it has been found 
impossible to associate with any certainty the. various limb-bones with the skulls, 
jaws, and teeth, and it has accordingly been thought better to define the various 
species on the evidence of the latter, and subsequently to describe all the limb-bones 
together ; with suggestions as to the species to which they may probably belong. 
1 Vide supra, p. 311. 
2 ‘ Jmirn. As. Soc. Beng.,’ vol. XL VII., pt. II., p. 2, pi. II. The specimen is compared to Fseudcelurus , 
not being then aware of the distinctive characters of in that genus. 
3 “ Osteographie,” Genus Felis, pi. XIV. 
•4 Mivart, ‘ Trans. Zool. Soc. Lon.,’ vol. X., p. 84 : Owen, “ Odontography,” p. 48S. 
the writer 
