NO. 7 TERTIARY APHELISCUS AND PHENACODAPTES GAZIN 7 



EXPLANATION OF PLATES 



Plate i 



Apheliscus and Phcnacodaptes from the early Tertiary of Wyoming 



Figs. 1, 2. Apheliscus insidiosus Cope: 1, Right ramus of mandible (U.S.N.M. 



No. 19162), lateral and occlusal views. 2, Left ramus of mandible (A.M. 



No. 15696), lateral and occlusal views. All four times natural size. Gray Bull 



lower Eocene, Big Horn Basin, Wyoming. 

 Figs. 3, 4. Phenacodaptes sabulosus Jepsen: 3, Right ramus of mandible (P.U. 



No. 13926), lateral and occlusal views. 4, Left ramus of mandible (P.U. 



No. 13391), lateral and occlusal views. All four times natural size. Silver 



Coulee (Tiffanian) upper Paleocene, Big Horn Basin, Wyoming. 



Plate 2 



Apheliscinae and Pentacodontinae from the early Tertiary of the 

 Rocky Mountain Region 



Fig. 1. Apheliscus insidiosus Cope: Left upper cheek teeth (A.M. No. 15696), 

 occlusal view. Four times natural size. Gray Bull lower Eocene, Big Horn 

 Basin, Wyoming. 



Fig. 2. Phenacodaptes sabulosus Jepsen: Right upper cheek teeth (P.U. 

 No. 13977), occlusal view. Four times natural size. Silver Coulee (Tiffanian) 

 upper Paleocene, Big Horn Basin, Wyoming. 



Figs. 3, 4. Aphronorus fraudator Simpson: 3, Right upper cheek teeth 

 (U.S.N.M. No. 9561, Pi from U.S.N.M. No. 9564), occlusal view. 4, Left 

 ramus of mandible (U.S.N.M. No. 6177, type specimen, with molars restored 

 from U.S.N.M. No. 9289, Pi to P 3 from U.S.N.M. Nos. 9537 and 9291), lateral 

 and occlusal views. All four times natural size. Fort Union middle Paleocene, 

 Crazy Mountain area, Montana. 



Figs. 5, 6. Pentacodon inversus (Cope) : 5, Left upper cheek teeth (U.S.N.M. 

 No. 15502), occlusal view. 6, Left ramus of mandible (A.M. No. 17038), 

 lateral and occlusal views. All twice natural size. Torrejon middle Paleocene, 

 San Juan Basin, New Mexico. 



