78 rOSSIL MAMMALIA OF THE 



convex ; the inner contoiu* (ib. i) is convex at the npper half, concave at the lower one ; the 

 inner border is sharply defined, as in Thjlacinus. The representative of the angnlar process 

 of the jaw in other Mammals is here directly and abruptly inflected inward, at the level of 

 the lower end of the condyle, as a horizontal ridge [a, a), which extends forward from 

 the inner side of the lower margin of the ramus to the entry of the dental canal {d), in 

 front of which the ridge curves and rises vertically with some subsidence and blunting to 

 the back part of the molar socket (?« 2), which is partly within, and is below the anterior 

 part of the base of tlie coronoid process {b). The inflected part of the lower, border of 

 the ranms is not much produced, but is most so near the angle, where the margin, broken 

 off" from the slab under scrutiny, is preserved in that containing the fore part of the 

 ramus with the teeth (fig. 11). The line of the inflected lower border of the jaw runs 

 nearly straight from the terminal condyle to beneath the dental canal. 



From the upper end of the condyle the hind margin of the rising branch (' ramus 

 ascendens,' ' perpendicular portion or ramus,' Anthropotomy) dips down before cnrving 

 forward and upward to rise almost vertically, or with a slight backward curve, to the 

 summit of the coronoid process {h). The concave cm've from the condyle is deep and 

 bold, giving a pedunculate character to the joint, at least at its upper part. The iimer 

 margin of the condyle is produced beyond the level of the inner surface of the rising 

 ramus, circumscril)ing that surface behind, as does the ridge anterior to the dental canal 

 in front. The apex of the coronoid process, if it were entire, would probably not extend 

 further back in relation to the condyle than in Thylacinus, fig. 5. 



From the summit of the coronoid the anterior margin of that process curves with, at 

 first, a bold convexity, subsiding near the base to change into the gentle concave line by 

 which the process commences, anteriorly, on the outside of the hind socket or hind part 

 of the socket of the last molar tooth. 



The tract of line forming the inner surface of the broad (antero-posteriorly extended) 

 and high coronoid, with that of the ' ramus ascendens ' below, is almost flat on the inner 

 side of the jaw here exposed. It is vertically concave through the production of the inner 

 part of the lower border, near that border, and is very feebly convex in the same direction 

 along the base of the coronoid ; in the fore-and-aft direction the flatness of the relatively 

 extensive tract of the inner surface of this part of the mandible is less affected. The inner 

 alveolar wall of the last socket makes an obtuse projection (below m 2, in fig. 10 a), and 

 it is thicker than the outer alveolar wall. In the horizontal plane the inner border of the 

 socket describes a more convex curve than does the outer border. The entire border is 

 obtuse; the socket is a full longitudinal irregular ellipse, and less deep than its length, 

 recalling the shallow bed in which rests the hind tubercular of Thylacolco and Felis. A 

 part of the socket of the anterior molar {m 1) is preserved, in front of which is the 

 impression, in slab, fig. 10, of the large premolar (j» 4). 



The fore part of the ramus with the teeth is almost as deep as it is long, the depth or 

 height of the ramus increasing from the incisive alveolus to the hind fractured part. A 



