SIWALIK AND NARBADA CARNIVORA. 
53—230 
proportionate length, and more sectorial character ; the latter being of course most 
marked in the blade. In Hycenarctos the inner cusp of the blade (a) is relatively 
small and placed in great part posteriorly to the hinder outer lobe (b) ; whereas in the 
bears it is much larger and placed completely on the inner side of the hinder outer 
lobe which is relatively small. This arrangement in Hycenarctos allows the main 
lobes of the blade to assume a truly sectorial character. It is very noteworthy that 
Prof. Huxley 1 has recorded an almost identical condition in the dogs, in the less 
specialized forms of which ( Otocyon ) the inner cusp (anterior internal cusp of Prof. 
Huxley) of the blade of m. i is relatively large, and placed on the inner side of the 
hinder outer lobe (anterior external cusp); while in the higher forms e.g. (Cams 
lupus) the former is small and placed posteriorly to the latter. In consequence of 
these different arrangements the line connecting the summits of the inner cusp and 
the hinder outer lobe of the blade (cusp-line of Prof. Huxley) is nearly transverse 
in Otocyon , but very oblique in the wolf. The corresponding line is transverse in 
Ursus, and very oblique in Hycenarctos. The talon of the carnassial of the latter has 
its bounding ridges considerably more developed than in the former. 
This tooth very closely resembles the carnassial of Dinocyon thenardi 2 ; the only 
appreciable difference between the two being that the talon is rather more developed 
in hycenarctos ; and that it carries two minute cusps, in place of one, behind the 
inner cusp (a) of the blade : these tubercular cusps are much lower than the inner 
cusp of the blade. The differences between the carnassials of these two genera are 
indeed much less marked than those existing between the corresponding teeth of 
certain genera of the modern dogs and foxes. From the lower carnassial of Cams 
lupus the corresponding tooth of Hycenarctos , except in respect of size, scarcely 
differs more than by the slighter development of the cusps of the talon : the blade 
is, however, somewhat lower and stouter ; but the whole tooth is more like that of a 
dog than that of a bear. 
The second true molar (m. 2) much resembles the corresponding tooth of Ursus 
arctos , but is relatively shorter and broader, and has its cusps and ridges more 
developed. In shape it is very close to the corresponding tooth of Dinocyon tlienardi : 
it also resembles the corresponding tooth of Amphicyon (pi. XXXII., fig. 4), but the 
cusj)s of the latter are more distinct ; a character still more marked in the true dogs. 
In the different stages of wear of the two specimens it is impossible to draw any 
distinction between this tooth and the second molar of Hycenarctos sivalensis. - 
The third true molar (mTF) has an almost circular crown, and in this respect is 
nearer to the true dogs than to either Ursus or Dinocyon. 
The canine is considerably smaller than the canine of Hycenarctos sivalensis , as 
may be seen by the measurements given below, and by a comparison of the figure 
with that of the upper jaw of the latter : it is also distinguished by having a more 
flattened inner surface, bounded by well-defined edges. This surface is more flattened 
l ‘ Pro. Zool. Soc.,’ 1880, p. 260, fig. 13, and elsewhere. 2 Filhol, op. cit., pi. III., figs. 4-5. 
M 
