304 Bulletin American Museum of Natural History. [Vol. XXXIV, 
‘those forms of the same size in the Clark Fork, where the genus makes its 
first appearance. There are obviously several species, indicated by size 
P.. primevus robustus 
(Paratype, Gray Bull beds, 
Bighorn basin, Wyo). 
P. primevus 
(Plesiotype, Cope skeleton, 
Gray Bull beds, Bighorn 
basin, Wyo.) 
No, 15286: 
= 
P. primevus hemiconus 
(Topotype, Gray Bull beds, 
Bighorn basin, Wyo.) , 
~ 
ge intermedius 
(Type,4 Gray Bull beds, 
Bighorn basin, Wyo.) 
P. copet 
e Ey (Type, Cope skeleton, Gray 
mi :\ Bull beds, Bighorn basin, 
Y N a Wyo.) 
Fig. 3. Upper teeth of species of Phenacodus. 
