4G— 12 INDIAN TERTIARY AND POST-TERTIARY VERTEBRATA. 
II. pala;iiidicus. 
11. namadicus. 
11. sivalonsis. 
Length of symphysis 
( 
Type sp. 
I. M. 
F. 149. 
B. M. 
40,893. 
5 0 
B. M. 
41,663. 
5-39 
f 
4T 
5-2 
5 '85 
7T 
Interval between canine 
8-2 
9-3 
7-2 
9-3 
9 9 
80 
Depth at pm. 1 . 
4-9 
5'2 
4-3 
4 65 
6-2 
4 6 
Longer diameter of canine 
2-26 
2-35 
1-67 
1-86 
2'14 
2-4 
)> ^ 
1*5 
1-96 
1-80 
1-8 
1-2 
1-23 
1-26 
1-3 
1-35 
9 
yy yy yy yy ^ • 
0-59 
0-62 
0’72 
0-9 
0-97 
0-9 
0-92 
I'O 
*5 
yy yy yy yy ^ 
1-8.5 
2-0 
1-84 
1-81 
1-33 1-24 
1-43 
1-5 
1 3 
From tlie occurrence of tlie small i. 2 in all the three specimens in which the 
superior surface of the symphysis is preserved, it seems probable that this tooth was 
originally present in the two specimens noticed by Falconer, in wdiich that part is 
wanting. The table of measurements shows that in specimens in which the depth 
of the mandible is the same, the symphysis is shorter in 11. 'paloeindicus than H. 
namadicus ; and this, coupled with the larger size of the first and third pairs of 
incisors, and the smaller size of the second pair, indicates the specific distinctness of 
the two forms.^ This is confirmed by fhe difference in the position of the canines, 
which are placed more nearly on a level with the incisors in II. namadicus than in 
H. palccindicus. 
Besides the shorter mandibular ramus, the latter species is distinguished from 
II. amphihius by the shorter sjunphysis ; by the equality in size of i. 1 and iTy ; and 
by the presence of the minute 172. 
Cranium . — The impossibility of deciding as to whether the crania figured in fhe 
“ F.A.S.,”^ under the name of H. palceindicus, and the similar cranium in the Indian 
Museum so named by Falconer,® really belong to that species, or to II. namadicus, or 
to both, has been already alluded to under the head of the latter species. The chief 
characters of these crania may now be briefly mentioned. They indicate an animal 
somewhat larger than the, existing race of II. ampMbius ; and are characterised by 
their prominent orbits, and their general shortness : the latter feature being shown 
by the small interval between the posterior border of the palate and the anterior 
zygomatic root, as well as by the extreme shortness of the pre-orbital constriction, 
and the backward position of the maxillary expansion. The last molar has its 
posterior border placed slightly behind the free border of the palatines ; which at 
once distinguishes these crania from those of all other species except one variety of 
II. sivcdensis. In that form, however, m. 3 does not extend in advance of the 
posterior border of the anterior zygomatic root ; whereas this is largely the case in the 
Narbada skulls ; the Siwalik skulls are also distinguished by their considerably 
longer shape, and longer pre-orbital constriction ; and by their narrower molars. 
The nasals of the Narbada skulls seem to have been shorter and wider than those of 
II. ampliibius. The shortness of the Narbada skulls is a character which accords 
equally well with both the forms of lower jaws from that formation. 
1 Before he had an opportunity of comparing all the specimens the present writer thought they might be identical. 
Plate LVII., figs. 1, 16; LVIII., figs. 4, 46. 3 “ Pal. Mom.,” vol. I., p. 147. 
