239—62 INDIAN TERTIARY AND POST-TERTIARY VERTEBRATA. 
The generic distinctness of Arctotherium is confirmed by the character of the 
femur, of which there is a specimen in the British Museum. This bone in the form 
of its 1 head ’ and 1 neck ’ is like the femur of Ursus, but is laterally expanded, as in 
Hycenarctos ; being on the whole intermediate between the two, but nearer to that of 
the former- 
Generic distinctness . — From the comparisons given above there can be little doubt 
of the generic distinctness of Hycenarctos from all the allied forms. In describing 
the Crag specimens Prof. Flower remarks 1 that “it is certainly very closely allied to 
the true bears, though in its dentition somewhat less specialized than the modern 
representatives of the group.” The observations recorded above strongly confirm this 
relationship, through Arctotherium ; but exhibit equally strongly, through H. 
palceindicus and Dinocyon , a marked affinity with the dogs. The writer is unable to 
agree with Prof. Flower in considering the dention of Hycenarctos as less specialized 
than that of Ursus ; its much more markedly carnassial character being in his own 
opinion a character of greater specialization. The simply tuberculate molar dentition 
of Ursus approaches more nearly than that of any other carnivorous genus to the 
molars of the bunodont Suina, and since it has lately been shown 2 that there are 
some remarkable indications of affinity existing between certain extinct Suina 
(Achcehodon) and the bear-like Carnivora, it is not impossible that this simple type of 
dentition may be a retention of, or a reversion to, an original primitive form. 
In the following diagram it has been attempted to indicate in the most 
provisional manner the probable relationship of Hycenarctos to allied Carnivora.. 
The present extent of knowledge does not permit the construction of a complete 
genealogical tree, and it does not necessarily follow that the genera placed in the 
lower lines are the direct ancestors of those in the higher lines with which they are 
connected by vertical lines. The genera placed on the same horizontal line indicate 
that there is at present no indication of one being the direct descendant of another : — 
Ursus —Arctotherium— Hysenarctos — 
\ r~ 
Canis (etc.) 
punjabiensis, sivalensis, palceindicus. i 
Dinocyon | Ceph 
Amphicyon 
HYiENID^S. 
V 
VlVEBRIDJE. 
Cynodictis. 
1 Op. cit. 
2 H. F. Osborn, “ On Achcenodon, an Eocepe Bunodont.” ‘Contributions from E. M. Mus. of Geol. and Archaeol. of 
Princeton College— Bulletin No. 3 ’—Princeton, U.S.A., May, 1883. 
