EAKYTIIEHIUM. 
173 
or less triangular in outline and was borne on three roots. Pm. 3 had a rectangular 
crown and was widest from side to side. Pm. 4 was also widest transversely ; its crown 
seems to have consisted of a broad anterior ridge (now greatly abraded) connected 
posteriorly at its outer and inner ends with the hinder border of the tooth. M. 1 is 
greatly worn, but seems to have been bilopliodont. M. '1 was bilophodont, the crests 
being widest at their inner ends. The inner half of the posterior crest was connected 
with the cingulum towards the middle of the posterior border. M. 3 is also bilopho- 
dont ; the anterior crest is somewhat S-shaj)ed, its inner end turning forwards on to 
the antero-internal angle of the crown. The posterior crest is curved with the 
concavity posterior. The dimensions of these teeth are given below. 
Mandible (PL XVII. tig. 5). — Tbe mandible, wanting much of the posterior region, 
was found associated with the above-described maxillae. It is chiefly remarkable for 
its extraordinarily massive construction, shown in the length of the symphysis and 
the depth of the rami. The symphysis is very long, extending back to the level of 
the hinder end of m. 1 ; its upper surface is spout-like and in front it carried a pair 
of large procumbent tusk-like incisors, and there may also have been a pair of small 
second incisors above and behind these, but this is doubtful. The ventral surface 
of the symphysis is broad and convex, at least posteriorly ; at about its middle and 
a little in front of the level of the anterior premolars the ventral border bears 
on either side a large blunt process {pr.), which projects forwards, outwards, and 
downwards. There is a large mental foramen {m.f.) on the middle of the outer 
face of the jaw above the base of this process, and a groove runs downwards 
and forwards from this opening ; there is also a second smaller opening above that 
just referred to. Beneath the cheek-teeth the ramus is very deep and its outer face 
nearly flat, while behind the symphysis the ventral border is convex from before 
backwards. The ascending ramus arises on the outer face of the horizontal ramus 
about midway between the ventral and alveolar borders ; it arches strongly outwards, 
and the anterior end of its base is beneath m. 2. From this point its anterior border, 
which is greatly thickened, slopes a little forwards, rising into the massive coronoid 
process {cor.), the horizontal upper edge of which is about II cm. above the level of 
the crowns of the teeth ; the whole of the condyle and the angular region of the 
mandible are wanting. 
Lower Dentition (PI. XVII. figs. 5, G). — Behind the incisors, to which reference lias 
already been made, there is a long diastema (13 cm.), the next tooth being the second 
premolar. The portion of the alveolar border of the jaw bearing the cheek-teeth seems 
to be raised considerably above the anterior edentulous portion. The anterior premolar 
{pm. 2) has a triangular crown and appears to have been supported on three roots, 
of which one is anterior, the other two arranged transversely p'lsteriorly. Pm. 3 and 
pm. 4 have each four roots and a nearly square crown, apparently bilophodont, at 
least in jiwn 4. M.l is greatly broken, the crown being almost entirely wanting; 
