432 Eaton — John Day Felidce in Marsh Collection. 



The tooth is not quite fully protruded. The order of 

 dental replacement, exhibited in this skull, should be 

 noted. Disregarding the incisors, none of which have 

 been preserved, there are actually in place and functional, 

 in the lower jaw, a permanent canine and a permanent 

 P 4 , and in the. upper jaw, on one side, all the permanent 

 premolars and molars. On the left side the alveolar 

 margin where P 2 should be has been destroyed. From 



Fig. 2. 



Fig. 2. — Pogonodon serrulidens, sp. nov. Holotype. X %• 



the foregoing it appears that the deciduous upper canines 

 remained in place until all the permanent upper cheek 

 teeth were fully erupted. The presence of P 4 in the 

 mandible renders it probable that the replacement of 

 the lower cheek-teeth also was nearly if not quite 

 completed, for in recent carnivores the lower carnassial 

 is the first permanent cheek-tooth to appear. The best 

 example at hand of a recent wild feline, showing the 

 dental replacement, is a skull of the bay lynx (Lynx 

 rufus), No, 0926, Y. P. M. Comparison of this lynx 

 skull with that of Pogonodon serrulidens shows that, the 

 replacement of the canines being at approximately the 

 same stage in the two skulls, the replacement of the cheek- 



