84 RHINOCEROS. 
The foramen lacerum is relatively small compared with that of Rhinoceros indicus, 
and the foramen ovale, which is distinct from it, is situated on a line internally 
with the glenoid articulation. 
The latter antero-posteriorly in comparison with its breadth, is relatively greater 
than in Rhinoceros indicus, and is directed more outwardly, and at its postero- 
external portion is more depressed. 
The post-glencidal tubercle is relatively short, thin, and broad compared with 
that of Rhinoceros indicus. It is obliquely compressed, and has one broad surface 
directed backward and inward ; the other, forming part of the articulation, present- 
ing outward and forward. 
As in Rhinoceros indicus, the root externally of the pterygoid processes, is tra- 
versed by a short but large canal, into which opens a foramen representing the 
associated foramina rotundum and spheno-orbitale. : 
The passage to the posterior nares, between the pterygoid processes and vertical 
plates of the palate bones, has about the same relative extent as in Fhinoceros 
indicus. 
The hard palate in the specimen is very much fractured, but the parts appear 
to have retained their natural relative position; and it is remarkable for its deep 
and narrow arched form. The molar teeth, in a nearly straight line upon each 
side, converge anteriorly, and are distant between the first premolars only nine 
lines, and between the anterior lobes of the seventh molars twenty-two lines. 
The inner sides of the molars, in advance of the posterior two, project internally 
beyond the alveolar margin, and gradually increase in this disposition to the first 
premolars, so that the passage between these latter and the hard palate forms 
nearly four-fifths of a cylinder. 
Inferior Maxilla.—(Pl. XIII. 2-4.) Of the two fragments of the lower jaw pre- 
served in Dr. Owen’s collection, which are both of the left side of two different 
adult individuals, the one contains the last two molars and half of that in advance, 
and the other contains the third to the fifth inclusive. The depth of the lower 
jaw below the posterior molar is twenty-eight lines, and its thickness fourteen lines. 
Superior Molars.—(P1. XII.) The superior molars are about three-fourths the 
size of those of Rhinoceros indicus, and present a very great degree of resemblance 
to those of Aceratherium incisivum. All possess a basal cingulum, which, however, 
is feebly developed at the outer side of the antero-external lobe, and is entirely 
obsolete at the base postero-internally of the fifth and sixth molars, and for a nar- 
row space internally upon the antero-internal lobes of the same pair of teeth. 
Upon the inner side of the base of the molars, from the second to the fourth in- 
clusive, it is better developed than in the same position in Aceratherium incisivum. 
In the seventh molar, the lobes are quite simple, neither of those within sending 
any sublobes into the single valley of the tooth, although they are very feebly 
bulging about the middle of their course. 
In the corresponding lobes of the two molars in advance, the bulging of that 
anterior successively increases, while that posterior in the same position is con- 
stricted. This bulging of the lobes diminishes the depth of the principal valleys to 
a degree corresponding to its successive increase forward. 
