SIWALIK AND NAEBADA PEOBOSCIDIA. 
13—194 
tubercle placed at tlie inner entrance of the transverse valley. Prom tlie height 
of the centre of the transverse valley in the larger tooth, it appears that in the 
complete tooth there must have been a slight longitudinal bridge, connecting the 
transverse ridges. The larger tooth is further distinguished from the smaller by 
the much greater thickness of the enamel. In the following table I have compared 
together the dimensions of the two teeth, together with those of the corresponding 
tooth of the European Binotherium giganteum :■ — 
Z). indicium, D. giganteum. D. pentapotamim. 
Width of last ridge SV 3’4 2-3 
Thickness of base of ridge 1'8 1-6 I’l 
Thickness of enamel 0-25 0‘i8 0-09 
Although, from its incomplete state, we are unable to compare the whole of the 
larger tooth with the corresponding tooth of Binotherium pentapotamice, yet the 
comparisons we have made are, I submit, sufficient to show the specific distinctness 
of the two. It now remains to see to what species the larger tooth should be 
referred. If we turn to the “ Palseontological Memoms ” of Dr. Ealconer,^ we shall 
find that the fragmentary molars and lower jaw of Binotherium indicum are of 
somewhat larger size than those of B. giganteum, while the former are further dis- 
tinguished by the great thickness of their enamel. In both these characters the 
imperfect tooth described above agrees with Dr. Falconer’s specimen, and I have 
therefore referred it to the same species. 
Dr. Falconer, in the notice mentioned above, has shown in what respects the 
lower jaw of Binotherium indicum differs from the lower jaw of B. giganteum. The 
fragmentary upper molar of the former species is distinguished from the correspond- 
ing tooth of the latter by its larger size and thicker enamel, by the great size of the 
tubercle at the inner extremity of the transverse valley (which is very small or 
wanting in B. giganteum), and by the elevation of the middle of the transverse 
valley. 
First lower true molar . — The only other tooth of Binotherium in the Indian 
Museum which I can refer to the same species, is the specimen represented in fig. 2 
of Plate XXXI, which was collected by Mr. W. T. Blanford in the Laki hills 
of Sind. The specimen is a complete three-ridged tooth, with all three ridges well 
worn. From the number of ridges it might be one of the “intermediate” molars 
of a trilophodont Mastodon, but the absence of any trace of a median longitudinal 
cleft across the ridges, together with other characters which I shall subsequently 
notice, shows that it cannot belong to a Mastodon, and that it must therefore be 
referred to a species of Binotherium. In the latter genus a three-ridged tooth can 
only be either a last milk-molar or a first true molar ; the great size of our speci- 
men shows that it cannot be a milk-molar, and it must consequently be a first true 
molar. The large size of the antero-posterior diameter in relation to the transverse, 
together with the convexity of the ridges being on the hinder side, shows that the 
* Vol. I, pp. 396, 404. 
D 
