1915.| Matthew and Granger, Lower Eocene Waseet and Wind River Faunas. 43 
Another new genus Prolimnocyon is structurally ancestral in dentition to 
Inmnocyon and Thinocyon and is represented by a skull and several jaws 
from the Gray Bull horizon of the Wasatch. Its dental formula is that of 
LPO L FAO 7 
A. f7. 
Mig; 37. 
Fig. 37. Vassacyon promicrodon, humerus, radius and vane, front views; from the 
skeleton No. 15161, Gray Bull beds, Big Horn Basin. 
Fig. 38. Vassacyon promicrodon, carpal bones and Hicial phalanx, natural size; above, 
scapholunar proximal view, dorsal view with magnum, unciform and cuneiform, distal view; 
below, ungual phalanx lateral and superior views. From skeleton No. 15161. 
the early Hyznodonts, but it is typically Oxyeenid in other respects, and 
indicates the approximation of these two families in the early Eocene. 
The reference of Ambloctonus and Paleonictis to the Oxyzenidee (Mat- 
