114 PROCEEDINGS OF THE GEOLOGICAL SOCIETY. [Nov. 3, 
The fourth premolar (P 4) offers a notable difference from that of 
Dichodon, and resembles in its smaller size and comparatively simple 
conical crown the homologous tooth of the Anthracotherium and 
Cheropotamus. The principal lobe is a higher and narrower pyra- 
mid than in those genera; but, as in them, it is a half-cone, convex 
only on the outer side, which is bounded by an anterior and a poste- 
rior worn angle or edge: the anterior edge descends to a small sharp 
tubercle on the inner and anterior angle of the base of the crown; 
the posterior edge terminates at the middle of the broad posterior 
basal ridge or ‘talon.’ The internal basal ridge rises into a poimt 
upon the middle of the inner surface of the principal lobe, and be- 
tween this point and the summit of that lobe there is a third small 
point or cusp. There is a well-marked anterior basal ridge. The 
third premolar (P 3) equals the fourth in vertical and antero-poste- 
rior extent, but is narrower transversely: the anterior and posterior 
trenchant margins of the pointed crown are sharper, but similarly 
disposed. There is no intermediate cusp between the angle of the 
internal basal ridge and the apex of the crown: the internal basal 
ridge is almost obsolete on the anterior half of the crown. The an- 
terior basal tubercle and the posterior talon are relatively smaller. 
The socket of the second premolar (P 2) shows that tooth to have 
been rather smaller than the third; but, like this and the fourth, to 
have had two fangs. It is situated close to the third.. The socket 
of the first premolar (P 1) is removed to a distance equal to the 
antero-posterior extent of both second and third premolars from those 
teeth: it shows the tooth to have been about half the size of the 
second premolar, and to have been implanted by a single fang, or 
rather by two connate fangs. A diastema of rather more than half 
the extent of the interval behind divides the first premolar from the 
canine (c). The socket of this tooth is close to that of the outer in- 
cisor (13), and bounds on each side the curved series of the six in- 
cisive sockets round the fore-part of the symphysis of the jaw, as in 
the Ruminants. The socket of the canine differs from that of the 
incisors by a slight superiority of size, and a feeble longitudinal pro-. 
jection from its inner wall, mdicating a groove on that side of the 
fang, such as we see in the lower canine of the Dichodon: the obli- 
quity of the socket is nearly parallel with that of the external imcisive 
socket. The sockets of the incisors are six in number, close together, 
more oblique, and showing their teeth to have been less procumbent 
than in the Hog; with long subcylindrical fangs, very slightly dimi- 
nishing in size from the third to the first or innermost. 
The parts of the lower jaw preserved are the symphysis and left 
ramus as far as the base of the coronoid process (Pl. VIII. figs. 1 & 3), 
and as much of the right ramus as supports the third and fourth pre- 
molars and the three true molar teeth (fig. 2). The entire lower jaw 
has been unusually long, narrow and shallow; but each ramus is 
thicker than in the Ruminants, though not so thick as in the Chero- 
potamus; its chief peculiarity is the small depth as compared with 
the size of the teeth, in which character it approaches the Dichodon.. 
The symphysis is long, narrow, almost horizontal, with the original 
