153—12 INDIAN TERTIARY AND POST-TERTIARY VERTEBRATA. 
Upper molar. — The specimen of an upper molar referred to above is represented, 
of the natural size, in figure 2 of plate XXIV.: it is implanted in a fragment of the 
right maxilla, which also shows the base of the preceding tooth : the perfect tooth is 
the last true molar. The tooth has unfortunately lost a considerable portion of the 
first outer column, but is otherwise perfect : it is in an early stage of detrition, the 
two hinder columns being untouched. The tooth is invested with a highly' rugose 
enamel, a character which, though apparently trivial, will be shown in the sequel to 
be of some importance. An inspection of the figure will at once show that the tooth 
belongs to one of the pentecuspidate selenodont Suina, in which the fifth column is 
well developed. The external surface of the one remaining perfect outer column 
bears a well developed vertical median ridge, diminishing in width from the base 
upwards ; the lateral borders of the base of the same surface are not produced out- 
wardly, so that they do not proj ect beyond the middle point of the base of this surface. 
The two outer columns are connected by a fold, which in the present condition of the 
tooth forms an angle, but in a worn condition would form an open loop. The second 
inner column is rounded externally, and concave internally ; it is separated by a 
shallow valley from the outer column of the same side. The first inner column is 
irregularly shaped. The transverse median valley of the crown is shallow, and does 
not become deeper as it passes outwards : there is no ‘ cingulum.’ The dimensions 
of the specimen are as follows : — 
In. 
Length . . . 1'6 
Width. ' . . . 1-68 
Height of second outer column 0-8 
Comparisons . — Comparing the specimen with the upper molars of the genus 
Anthracotherium, we find that in typical species of the latter, as A. magnum / 
A. alsaticum 2 and A. silistrense (plate XXIII. fig. 10) the fold connecting the two 
outer columns is more compressed, and so to speak, more pinched in, and does not 
form a wide distinct liorse-shoe-like loop, but has its outer service flat and bounded 
by distinct borders, forming a Y-shaped shield on the outer surface of the crown. 
In some species, however, as in A. cuvieri, and especially in the molars of that 
species from Piedmont in the British Museum already mentioned, there is a better 
defined loop, but still much less marked than in the present specimen. The 
shallowness and even depth of the valleys, of the latter, and the forms of the columns, 
as well as the rugose structure of the enamel, are, however, characters of the genus 
Anthracotherium, as distinct from Hyopotamus , and the specimen has accordingly been 
provisionally referred to the former genus. It has, however, characters distinctly 
approximating it to Hyopotamus, to mark which affinity it has been designated 
Anthracotherium hyopotamoides. In size it is intermediate between A. magnum and 
A . cuvieri. It will be shown in the sequel that the resemblance of the tooth is so 
close to an upper molar from the same locality (pi. XXIV., fig. 3) provisionally 
l See BlainviUc “ Osteographie,” Anthracotherium. 2 Filhol. op. cit. 
