84 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. 128 



MEASUREMENTS IN MILLIMETERS OF DENTITIONS IN SPECIMENS OF 



Leptotragulus medius 



CM. 



No. U.S.N.M. 



2g86 No. 



Type 16549 



Length of upper cheek tooth series, P'-M^, inclusive 34.5 



Length of upper cheek tooth series, P^-M^, inclusive 31.0 29.3 



Upper molar series, M*-M^ inclusive 20.4 19.5 



P', anteroposterior diameter : transverse diameter* 5.5 : 3.4a 



P^ anteroposterior diameter : transverse diameter 5.8 : 4.6 5.8 : . . . 



P*, anteroposterior diameter : transverse diameter 5.2 : 5.8 5.3 : 5.5 



M*, anteroposterior diameter : transverse diameter* 5-9: 7-3 6.2 : 7.2 



M^ anteroposterior diameter : transverse diameter 7.2 : 8.76 7.2 : 8.gb 



M\ anteroposterior diameter : transverse diameter 7.3: g.2b 7.3 : 8.9^ 



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



No. No. 



20.361 20365 



Length of lower cheek tooth series, Pi (at alveolus )-M3, in- 

 clusive 48.0a 



Length of lower cheek tooth series, P2-M3, inclusive 38.3 38.60 



Lower premolar series. Pi (at alveolus) -P4, inclusive 25.00 



Lower molar series, M1-M3, inclusive 23.0 23.4 



Pi, anteroposterior diameter (at alveolus) : greatest trans- 

 verse diameter 4.7 : 3.6 



P2, anteroposterior diameter 5.0 



P3, anteroposterior diameter : greatest transverse diameter . . 5.9 : . . . 5.8 : 3.2 



P4, anteroposterior diameter : greatest transverse diameter . . 5.8 : . . . 6.2 : 4.1 



Ml, anteroposterior diameter : transverse diameter of tal- 



onid 6.1:... 6.1:5.2 



Ma, anteroposterior diameter : transverse diameter of tal- 



onid 6.7: .. . 6.9 : 5.8 



M3, anteroposterior diameter : transverse diameter of trig- 



onid 10.6 : . . . 10.7 : 6.2 



a. Approximate. 



b, Margin of enamel lingually. 



* 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. 



LEPTOTRAGULUS CLARKI.^g new species 

 Plate 17, figure i 



Type. — Right ramus of mandible with Pi and P3-M3, U.S.N.M. 

 No. 20378. 



Horizon and locality. — Protylopus quarry, Myton pocket, 6 miles 

 east of Myton, Uinta Basin, Utah. 



Specific characters. — Size only a little smaller than Leptotragulus 



medius but with teeth relatively much more slender. P3 and P4 with 

 posterior crests from protoconid less divergent. 



*6 Named for Dr. John Clark. 



