SIWALIK AND NARBADA CARNIVORA. 
61—238 
which is much worn, only shows the disks, which are confluent, of two lobes, the 
anterior small talon, which is so well defined in Hycenarctos , being wanting ; but 
there is the great agreement of a mesial inner tubercle placed opposite the transverse 
axis, as in Hycenarctos. 
u 4. A square molar [m. 1], consisting of two outer and two inner cusps, the 
outer pair having the discs confluent, and also the inner. It is more moderate in 
form than the Siwalik tooth, and resembles the last of Hycenarctos. 
u 5. A last molar [m. 2], as in Hycenarctos , which, instead of being quadrate, 
has the inner posterior discous surface produced behind, so as to make the tooth 
oblong instead of square. The outer line, as in the Siwalik fossil, consists of two 
tubercles.” 
The upper carnassial of Arctotlierium is essentially that of a bear, the lobes of 
the blade not having the marked sectorial character of those of Hycenarctos [compare 
woodcut fig. 7, and plate XXX., fig. 2) : that character being most marked by the 
deepness of the cleft between the two. The true molars of the former are inter- 
mediate between those of JJrsus and Hycenarctos : the form of m. 2 approaching 
nearest to its homologue in H. punjabiensis. 
In the palate the backward extension of m. 2 behind the anterior root of the 
zygoma in Arctotlierium is in excess of that which occurs in the last-named species, and 
is, therefore, very different from H. sivalensis. The facial portion of the skull is much 
shorter than that of the "latter ; the profile of the face markedly concave, and the 
frontal region more prominent: in the latter characters there seems to be a 
resemblance to H. palceindicus , but the dentition of that form is widely different. 
In the mandible there seem to have been four premolars each of the first 
three inserted by a single fang, but the fourth having two fangs : the latter tooth is 
shorter and thicker than the corresponding tooth of II. sivalensis. The number, and 
mode of implanation of the premolars is the same as in JJrsus. The carnassial 2 is of 
a much less distinctly sectorial nature than that of Hycenarctos, being about inter- 
mediate between that tooth and the carnassial of JJrsus. The second and third 
premolars are also intermediate between the corresponding teeth of the two genera. 
From the suppression of pm. 1, the double roots of pm. 3 , the squareness of m. 1 ? 
and the smaller extent of the backward prolongation of the talon of m.'2 , it is pretty 
certain that the South American fossil is generically distinct from JJrsus, and the 
above-mentioned comparisons leave as little doubt that it is equally distinct from 
Hycenarctos : it forms in fact a genus almost precisely intermediate between the other 
two : II. punjabiensis being the species of Hycenarctos most nearly related to it. From 
the study of the teeth Dr. Falconer came to the conclusion that while Hycenarctos 
was probably carnivorous, Arctotlierium subsisted on a vegetable diet. The writer is 
unable to see that Arctotlierium presents any especial relationship to JJrsus ornatus. 
1 There is some confusion in Dr. Falconer’s note on these teeth. 
2 Gervais, * Ann. Sci. Nat.,’ op. cit., pi. V., fig - . 1. 1 
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