NO. 8 UPPER EOCENE ARTIODACTYLA — GAZIN 33 



CM, 



No. U.S.N.M. U.S.N.M. 



1 1 86s No. No. 



Type 20440 2043s 



M\ anteroposterior diameter : transverse diameter* 6.3 : j.'j 6.3 : ^.^ 



M^, anteroposterior diameter : transverse diameter . 6.6 : 8.7a d.'j : 8.6 6.7 : 8.3 

 M*, anteroposterior diameter : transverse diameter. . . . : 8.5 6.3 : 8.2 6.5 : 8.2 



U.S.N.M. U.S.N.M. 



No. No. 



20438 20437 



Length of lower cheek tooth series, C-M3, inclu- 

 sive .... 48.0a 49.0a 



Length of lower cheek tooth series, P1-AI3, inclu- 

 sive 4340 44.0a 



Lower premolar series, P1-P4, inclusive 22.5 23.0a 



Lower molar series, M1-M3, inclusive .... 20.8a 21.0 



C, anteroposterior diameter : greatest transverse 



diameter 4.1a : 2.4 .... 



Pi, anteroposterior diameter : greatest transverse 



diameter 4.2a : 2.4 .... 



P2, anteroposterior diameter : greatest transverse 



diameter 5.5:2.1 6.1:2.2 



Ps, anteroposterior diameter : greatest transverse 



diameter 6.3 : 2.6 6.8 : 2.7 



P4, anteroposterior diameter : greatest transverse 



diameter 6.2:... 6.0:3.9 6.1:3.6 



Mj, anteroposterior diameter : transverse diameter 



of talonid 6.2a : 4.4 6.3 : 4.7 6.3 : 4.9 



M2, anteroposterior diameter : transverse diameter 



of talonid 6.70:4.7 6.5:5.0 6.2:... 



Ma, anteroposterior diameter : transverse diameter 



of trigonid : 4.7 8.7 : . . . 



a. Approximate. 



* Measurements of posterior upper premolars are taken anteroposteriorly across outer por- 

 tion and transversely perpendicular to outer margin. Those of upper molars are taken 

 anteroposteriorly perpendicular to anterior margin and transversely across anterior portion 

 of tooth, 



PENTACEMYLUS LEOTENSIS," new species 



Type. — Rostral portion of skull and left ramus of mandible, P.U. 

 No. 1 63 10. 



Horizon and locality. — Upper Uinta C, Leota Ranch artiodactyl 

 quarry, Uinta Basin, Utah. 



Specific characters. — Size distinctly smaller than Pentacemylus 

 progressus. Premolars relatively small and separated by short diaste- 

 mata anterior to P^ and P4. 



Discussion. — So far, all the known material of Pentacemylus leoten- 

 sis, which consists of approximately a couple of dozen jaws and 

 maxillae, was obtained by Princeton University from a quarry at the 

 old Leota Ranch on the west side of the Green River several miles 



11 Named from the Leota Ranch. 



