BAETTHEEIUM. 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 bilophodont. M. 2 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-shaped, 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. fig. 6). — The mandible, wanting much of the posterior region, 

 was foitnd 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 boi'ders ; 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 11 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 Pentition (PI. XVII. figs. 5, 6). — Behind the incisors, to which reference has 

 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 

 (jpm. 2) has a triangular crown and appears to have been supported on three roots, 

 of which one is anterior, the other two arranged transversely posteriorly. Pm. 3 and 

 pm. 4 have each four roots and a nearly square crown, apparently bilophodont, at 

 least m pm. i. M.l is greatly broken, the crown being almost entirely wanting; 



