PLATE IV. 



Fig. 1. ff2/™'^oc?ow pma'c^ens, Lambe ; left maxilla with premolar and molar teeth. Type, 



Page 39. 

 Fig. 2. The same specimen, outer aspect. 



Fig. 3. Hyracodon priscidens, Lambe ; anterior end of mandible, outer view from the left. 

 Fig. 4. The same specimen, seen from above. 



Fig. 5. Aceratherium mite, Cope ; left upper third molar, seen from below. Page 48. 

 Fig. 6. ? Leptaceratherium trigonodon, Osb. and "Wort. ; right upper third molar, as seen 



from below. Page 44. 

 Fig. 7. Aceratherium occidentale (Leidy) ; left lower third molar, view from above. Page 44. 



pr., protocone ; d., deuterocone ; tr., tritocone ; ie., tetartocone; c, canine ; P2, second 

 premolar. 



