1919] Merriam: Tertiary Mammalian Faunas of Mohave Desert 565 



the metaconid-metastylid column presents a sharper, narrower, inner 

 gutter. The form represented by no. 21346 is presumably distinct 

 from the specimens referred to P. tantalus. It may be referred tenta- 

 tively to P. fairbanksi, but possibly represents a third type in the 

 Ricardo fauna. 



Fig. 183. Pliohippus fairbanksi? Merriam. P s to P 4 , no. 21346, natural size. 

 Eieardo Pliocene, Mohave Desert, California. 



Comparative Measurements 



P 3 , anteroposterior diameter .... 



P 3 , transverse diameter 



P 4 , height of crown, outer side 



P 4 , anteroposterior diameter .... 



M 1 , anteroposterior diameter 

 M 1 , transverse diameter 



- a 



3& 



§ o£ 



!"•« a 



Ph 



: : P. fairbanksi, 

 ! | no. 22307 



a £ 



— i 



• -04 ° 



■"Hi & 



Ph' 



25.2 

 26 



00 



.5 °»2 



eld 



u is 6 

 ■ H C 

 Ph 



. P. tantalus, 



i i Tvpe, 



; : no. 19434 



55 mm. 



51.5 





53 



48 



25 



25.6 



24.8 



27.2 



24.8 



26.4 



25 



26.7 



22 

 25.2 



24.4 



24 



Measuremnts of no. 21346 



Length anterior border P 2 to posterior border P 4 85.5 mm. 



P 2 , anteroposterior diameter 29 



P 2 , transverse diameter 15.2 



P 3 , anteroposterior diameter 27.9 



P;„ transverse diameter 15.2 



P 4 , anteroposterior diameter 29.6 



P 4 , transverse diameter 15.5 



Mt?, anteroposterior diameter 25.5 



M x ?, transverse diameter 14.2 



