60 FOSSIL MAMMALIA OF THE 



figured, of the natural size, in PL III, fig. 8. This also consists of a left mandibular 

 ramus with the outer side exposed, but wanting the hind half of the ascending branch 

 and the fore part, if not the whole, of the symphysis. It shows well the three trico- 

 nodont molars and the sockets of the anterior teeth as far as that of the first premolar. 

 Beneath it is a ' foramen mentale,' and behind, under the second premolar, is another 

 outlet of the dental canal ; the inlet of this may be seen at the hind fractured part of 

 the jaw. The anterior boundary of the outer crotaphyte depression is well marked ; it 

 is angular anteriorly, the corner just rounded off; the lower horizontal boundary projects 

 as it recedes, recalling a character of the mandible of Thylacinus. The outer plate of the 

 ramus falls sheer from the alveoli, not swelling out first, as the inner plate does. Two 

 thirds down, the outer plate begins to swell out and curve to form the thick convex lower 

 border of the ramus. 



The bone is marked by fine longitudinal striae. There is no trace of the longitudinal 

 depression shown in fig. '7. The three molars occupy an alveolar tract slightly exceed- 

 ing that in the type-specimen. Like it, I suspect the present jaw may have come from 

 an animal not fully adult. 



In the magnified view (3 diam.) of the crown oi m 2 (fig. 8 a) the vertical indent is 

 shown at the hind border of the hind cone, and a minute notch and prominence appears 

 at the fore part of the base of the front cone, which the specimen (fig. 9 a) shows to be due 

 to the beginning of the inner ' cingulum.' 



Triconodon mordax (?). Plate III, figs. 9, 9 a, 10, 10 a. 



The specimen, PI. Ill, fig. 9, nat. size, 9 a, second molar, magn. 4 diam., is a part of a 

 right mandibular ramus, with the three molars and the sockets of the four premolars, 

 showing the inner surface. In exposing the triconodont molars the fore part of the first 

 [m i) flew off, leaving, however, a distinct impression of its two anterior cones. 



The cingulum traversing the base of the inner side of the crown of m 2, and turning 

 up to the fore margin of the first cone and the hind margin of the last, is here instruc- 

 tively displayed (fig. 9 a), as is also the continuation of the cingulum into a small hind 

 basal cusp of the last molar {m 3). The cingulum thus limited to the inner side of the 

 lower molars is here minutely tuberculate. The crown of the second premolar [p 2) shows 

 a main median cone with the apex shghtly recurved, and a fore and hind basal cusp, the 

 latter being the larger. 



The symphysis begins behind at the vertical line dropped from the interspace between 

 the first and second premolars. The inner part of the lower border of the ramus is pro- 

 duced to form the lower boundary of the longitudinal groove extending forward from near 

 the entry of the dental canal. 



In size, especially in the extent of the three molars, this specimen shows a slight 



