84 



THE WHITE RIVER BADLANDS 



two, was doubtless fully as large as the present day leopard 

 and apparently much more powerful. (Plates 27 and 28). 

 The two represent well separated stages in the evolution of 

 saber-tooth cats, and while Dinictis seems to have reached 

 as high a stage of specialization as Hoplophoneus, it was evi- 

 dently fitted to a somewhat different life. 



An important feature of the lower jaw is the extreme 

 downward projection of its anterior portion. This seems to 

 be a co-incident feature necessitated by the unprecedented 

 development of the powerful canine teeth already mentioned. 



Figure 29 — Heads of White River Saber-tooth tigers showing open 

 jaws ready for attack, (a) Hoplophoneus primaevus (b) Dinictis 

 squalidens. Matthew. 



These upper canine teeth curve forward and downward 

 nearly parallel with each other, and passing behind the 

 much smaller lower canines, continue approximately to the 

 lowest portion of the anterior downward prolongation of the 

 chin. In general they are laterally compressed and the 

 edges are more or less serrulated. They are implanted by a 

 strong fang and reach two and one-half or three inches in 

 length. In Hoplophoneus, these fangs were very long and 

 slender and the protecting jaw flange was correspondingly 

 deep. Dinictis had shorter canines and a less prominent 

 jaw flange. 



