54 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. 128 



no restoration was made. This error was corrected in Thorpe's illus- 

 trations (1937, figs. 16 and 17). 



Marsh stated that the horizon for "H. hreviceps" was nearly the 

 same as that for Eomeryx {P. pumilus), which may mean little more 

 than near the White River. This would suggest lower "C" or upper 

 "B." Although Thorpe gives the horizon as "C," I suspect that it is 

 very low in this level, or to judge by the development of the dentition 

 I would be inclined to regard it as more likely from Uinta B. 



MEASUREMENTS IN MILLIMETERS OF DENTITIONS IN SPECIMENS OF 



Protoreodon parvus 



P.U. 



No. Y.P.M. 

 10398 No. 



Type 1 1891 



Length of upper cheek tooth series, C (at alveolus) -M', 



inclusive 67.0 



Length of upper cheek tooth series, P* (at alveolus )-M^ 



inclusive 56.0 



Upper premolar series, P* (at alveolus) -P*, inclusive... 26.8a 29.5 



Upper molar series, M*-M', inclusive 26.4 27.7 



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

 verse diameter 8.0 : 7.0 



P', anteroposterior diameter : transverse diameter* 7.3 : 7.4a 7.8 : 7.5 



P^ anteroposterior diameter : transverse diameter 6.7 : 8.8 6.5 : 8.8 



M\ anteroposterior diameter : transverse diameter* 8.0 : 10.2 8.8: lo.o 



M', anteroposterior diameter : transverse diameter 8.8 : 11. 4 9.4 : 12.0 



M*, anteroposterior diameter : transverse diameter lo.o : 12.8 lo.o : 13.0 



U.S.N.M. 

 No. 

 20383 

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



inclusive 6o.oa 



Lower premolar series, Pi (at alveolus) -P*, inclusive 30.0a 



Lower molar series, M1-M3, inclusive 30.5 



Pi, anteroposterior diameter (at alveolus) : greatest 



transverse diameter 8.0a : 5.2a 



Pa, anteroposterior diameter 6.0a 



P3, anteroposterior diameter : greatest transverse diame- 

 ter 8.9 : 4.3 



P4, anteroposterior diameter : greatest transverse diame- 

 ter 8.6a : 5.7 8.0 : 4.7 



Ml, anteroposterior diameter : transverse diameter of tal- 



onid 8.2 : 6.5 8.1 : 6.2 



Ms, anteroposterior diameter : transverse diameter of tal- 



onid 8.8 : 7-5 8.5 : 6.8 



M3, anteroposterior diameter : transverse diameter of trig- 



onid : 7-5 i3-8 : 6.8 



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. 



