SIWALIK AND NARBADA PROBOSCIDIA. 
23—204 
be tliorouglily cleaned from matrin, I have not given a figure of it. Its length is 
3-5 inches, and its greatest width 2’ 2 inches. 
First upper true molar. — The much worn tooth represented in fig. 4 of 
Plate XXXII has a very convex masticating surface, and therefore belongs to the 
upper molar series, and to the left side of the cranium, as is shown by the curvature 
of the ridges ; as it agrees so closely in size with the last-mentioned specimen, and 
carries three transverse ridges, it must be the first true molar. The first and the 
tliird ridges are the most worn, all traces of the median longitudinal cleft having 
been obliterated in these ridges ; in the second ridge a portion of this cleft still 
remains, the masticating surface being consequently divided into two incomplete 
dentine islands, of which the one on the lower side of the figure is the larger ; this 
side is consequently the inner side of the tooth. The length of tliis specimen is 
3 '6 inches, and its greatest width 2’3 inches. 
This tooth is of great value, because it enables us to show that the first 
true molar of FinotJierium indicum represented in fig. 2 of Plate XXXI cannot 
belong to this species of trilophodont Mastodon, to which on first sight it might be 
assigned. It will be seen, on comparing together the two teeth, that though the 
tooth of the Mastodon is the most worn of the two, as is shown by its lower ridges 
and wider dentine surfaces, yet still a trace of a median longitudinal cleft remains 
in the second ridge, while in the much less worn 'Dinotherium tooth no such trace 
is visible. The latter tooth, as a minor character, is further distinguished by the 
much greater thickness of its enamel. 
Second upper true molar. — The large tooth represented in fig. 1 of the same 
plate was collected by Mr. Theobald in the Punjab, and is an upper molar of the 
left side, and from its general characters evidently belongs to the same species 
as the last. Since this tooth carries three transverse ridges, and is larger than any 
of the preceding specimens, it must evidently be the last of the ‘intermediate’ 
molars, or, in other words, the second true molar. The greater portion of the 
anterior ridge and talon of this tooth has been broken away, though the other two 
ridges are complete ; the median ridge, and especially its inner column, has been 
considerably abraded by detrition ; the enamel of the last ridge is not perforated. 
A distinct median and longitudinal cleft divides each ridge into an inner and an 
outer column ; in each of the two transverse valleys there is a tubercle on the 
inner side of the median cleft closely applied to each side of the ridges. There is 
in consequence a slight obstruction at the bottom of each of the valleys which are, 
however, mainly characterized by being free and open; a large blunt tubercle 
occupies the mouth of the inner side of each valley. The ridges are nearly straight, 
which seems to indicate that the curvature which we observed in the last milk- 
molar gradually dies out in the succeeding teeth ; the ridges when unworn seem to 
have carried cusps like those of the preceding teeth. The posterior talon carries 
two distinct cones, the innermost of which is the larger of the two. The enamel 
is smooth and of considerable thickness ; the dentine islands of the inner columns 
