HISTORY OF THE CARNIVORA 



563 



into one and that the trenchant ridge was a superadded ele- 

 ment. The fourth upper premolar was a sectorial lilce that of 

 the Fissipedia, but of an unfinished, ineffective sort. The third 

 lower molar was very similar in shape to the carnassial of the 

 cats and was composed of only two large, thin and trenchant 

 cusps, which made a shearing blade, having lost the inner cusp 



Fig. 277. — ]Hy(Bnodon horridus, a White River tcreodont : in the background, iLepto- 

 meryx mansi. Restored from skeletons in the American Museum of Natural 

 History. 



of the primitive triangle and the heel. The first and second 

 molars were like the third except in size and in retaining a 

 vestige of the heel. The premolars were large and massive, 

 almost hyena-like, which suggested the generic name. The 

 canines were prominent and strong. 



The skull, as in almost all fcreodonts, was relatively ^•ery 

 large, but in the various species there was considerable differ- 

 ence of shape ; more commonly it was long and narrow, with 

 elongate jaws, and was quite wolf-like in appearance, but in 



