NO. 8 UPPER EOCENE ARTIODACTYLA — GAZIN 89 



Horizon and locality. — Upper Uintan, Sespe formation, Tapo Ranch 

 or C.I.T. loc. 180, north side of Simi Valley, Ventura County, Calif. 



Discussion. — Leptoreodon (H.) edwardsi is a little smaller than 

 Leptoreodon marshi, but clearly belongs to Leptoreodon rather than 

 Leptotragulus as Stock has shown. P^ and P^, though worn, show no 

 evidence of a tritocone as in Leptotragulus. P* is transversely broad 

 as in Leptoreodon but the deuterocone would appear to be perhaps 

 somewhat less crescentic than in L. marshi, certainly less so than in 

 Leptotragulus. The lower dentition belonging to C.I.T. No. 1840, 

 designated as a paratype, shows advanced wear, but P4 has a promi- 

 nent, rounded metaconid. The bifurcation of the posterior crest 

 posterointernally has also been noted in P. marshi material. The an- 

 terior crest, however, shows a somewhat more sharply flexed anterior 

 extremity suggesting a distinct parastylid cusp as in Leptotragulus, 

 although this is clearly not present in P2 and P3. The latter two teeth 

 are slender, and P2 as well as P3 has a weak posterointernal crest 

 rather than a distinct metaconid which joins the outer crest nearer 

 the apex of the protoconid than is noted in L. marshi material. 



MEASUREMENTS IN MILLIMETERS OF DENTITIONS IN SPECIMENS OF 



Leptoreodon (Hesperomeryx) edwardsi 



C.I.T. 



No. 



1839 

 Type 



Length of upper cheek tooth series, P^-M'', inclusive 37.70 



Upper molar series, M^-M^ inclusive 21.3 



P^ anteroposterior diameter : transverse diameter* 6.3 : 3.1 



P", anteroposterior diameter : transverse diameter 6.5 : 3.6 



P*, anteroposterior diameter : transverse diameter 5-7 : 6.3 



M*, anteroposterior diameter : transverse diameter* 6.3 : 8.2 



M^ anteroposterior diameter : transverse diameter 7.7 : 9.8 



M^ anteroposterior diameter : transverse diameter 8.0 : lo.o 



C.I.T. 



No. 

 1840 



Length of lower cheek tooth series, P2-M3, inclusive 41. i 



Lower molar series, M1-M3, inclusive 35.0 



P2, anteroposterior diameter : greatest transverse diameter 5-5 : 2.0 



P3, anteroposterior diameter : greatest transverse diameter 6.4: 2.9 



P4, anteroposterior diameter : greatest transverse diameter 6.4 : 3.6 



Ml, anteroposterior diameter : transverse diameter of talonid 6.3 : 5.2 



M2, anteroposterior diameter : transverse diameter of talonid 7.3 : 6.1 



M3, anteroposterior diameter : transverse diameter of trigonid 10.2: 5.9 



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. 



