318 PALAEONTOLOGY 



Sp. Triconodon mordax. — This name is proposed for a small 

 zoopliagous Mammal, whose generic distinction is shown by 

 the shape of the crowns of the molar teeth of the lower jaw, 

 which consist of three nearly equal cones on the same longi- 

 tudinal row, the middle one being very little larger than the 

 front and hind cone ; and these cones are not complicated by 

 any cingulum or accessory basal cusp. 

 The convex condyle is below the level 

 of the alveoli, and there is no angular 

 F - qi process projecting beneath it. The co- 



Jaw of Triconodon mordax ronoid process is broad and high, with 

 (nat. size), Purbeck. j ts hmder point not extended so far 

 back as the condyle ; the depression marking the insertion of 

 the temporal muscle extends nearly to the lower border of 

 the jaw. There are the obscure remains of three broken 

 incisors, and the point of apparently a canine ; next come the 

 two stumps, or broken roots of a small premolar ; then the 

 crown of a second double rooted premolar, which show a 

 principal cone and a small anterior cusp ; the next tooth is 

 wanting ; then there is a larger premolar, with the two fangs 

 raised some way out of their socket : the crown of this tooth 

 shows a principal cone, with a small anterior and large poste- 

 rior talon ; it rises, apparently from partial displacement, 

 higher than the succeeding molars ; these are three in number, 

 and present the characteristic three-coned structure already 

 described ; each cone is smooth, and convex externally. The 

 three cones seem to answer to the three middle or principal 

 cones of the molars of AmpMlestes and Phascolothcrium, but 

 the front and hind cones are raised to near equality with the 

 middle cone in Triconodon. 



The lower jaw of this species, in the relation of the condyle 

 to the lower border, resembles that of Phascolothcrium more 

 than that of Amphithcrium, but it differs from both ; there is 

 not the same gradual curve from the condyle to the symphysis 



