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University of California Publications in Geology [Vol.8 



More information on the range of variation in that species is neces- 

 sary and especially is it desirable to have more definite knowledge 

 of the characters separating it from E. occiclentalis. 



A single cheek-tooth (no. 21698, figs. 3a and 3&) from Astor Pass, 

 kindly presented by Professor Jones, represents a type with dimensions 

 smaller than those in the skull obtained by Mr. Hood. The fossettes 

 are rather narrow. The enamel is somewhat less complicated than 

 that in the skull specimen. This specimen taken by itself might be 

 referred to Equus occiclentalis, but the writer is inclined to think that 

 it represents the same species as that seen in the skull specimen. 



Measurements 



Hood 

 Specimen 



Astor Pass No. 21698 



Length of upper premolar series, without P 1 107. ram. 



I'-, anteroposterior diameter 40.4 



transverse diameter 28.4 



Pa, anteroposterior diameter 34. 



P3, transverse diameter 31.2 



P 4 , anteroposterior diameter 31. 



P*, transverse diameter 29. 



Mi, anteroposterior diameter 30.6 



M 1 , transverse diameter 29.4 



M'-, anteroposterior diameter 31.5 30.5 



M 2 , transverse diameter 27.5 26.8 



M2, length of crown al03. 



Transmitted October 24, 1914. 



