336 Bulletin American Museum of Natural History. [Vol. XXXIV, 
Its relative abundance in the different horizons of the Bighorn and Wind 
River basins is shown in the list of specimens in the Museum collection. 
Lost Cabin 2 specimens 
Lysite . 0 : 
Gray Bull 
Sand Coulée 
Clark Fork 
P. primevus robustus 
(Type, Gray Bull beds, 
Bighorn basin, Wyo.) 
Me 75e 7S 
ed: 
ai a | P. primevus 
a A WO. ANY - (Plesiotype, Cope skele- 
of US oN | ton, Gray Bull beds, Big- 
ee ti Sng \ horn basin, Wyo.) 
P. primevus hemiconus 
(Topotype, Gray Bull 
beds, Bighorn basin, 
Wyo.) 
P. intermedius 
(Type, Gray Bull beds, 
Bighorn basin. Wyo.) 
Za P. copet 
~ : Ca 
I Cit (Type, Cope _ skeleton, 
. Gray Bull beds, Bighorn 
rag UN basin, Wyo.) 
Fig. 5. - Lower teeth, crown views, of species of Phenacodus. 
Y 
