258 



EOCENE FAUNA. 



ti(l<r, and which differ, so far as known, from Oxyrpna in the absence of the 

 preglenoid crest. I suspect tliat these forms. constitute a family by them- 

 selve.s, and for the present, until our knowledge of them is fuller, I define 

 it by this character. 



Fig. 10. 



Fig. 10.— Maudible of Oriiwna forcipala Cope. one-Iial f uatural size ; a from above, b from left siile. From 

 Kupoit Expl. burv. W. 100th Mer., G. M. Wheeler, vol. iv, pt. ii. 



Shortly after the publication of my arrangement of the Credonta in 

 1880,* I obtained a good deal of additional material, which cMiabled me to 

 improve it in several respects. A number of genera have been added, and 

 the characters which distinguish the Miachhc and Oxi/iruifhr have been more 

 fullv brouofht out. The il//rtc«/fP. differ from all other families in having the 

 foui'th superior premolar sectorial as in the true Carnirora, while the true 

 molars are tubercular. In O.ijidud, the fourtli superior ])remolar di.splays 

 no indication of .sectorial structure, the fir.st true molar assuming that char- 

 acter. In Sti/p(il()j)hu.s and allies, the second superior true molar is more or 

 less .sectorial, and the first true molar and even the fourth premolar iii some 

 of the genera, develop something of the same character. But there is every 



* rroceeUiiigH AmiT. I'hilon. Soiifi.v, p. Tti. 



