1913] 



Merriam: Fauna of Orindan and Siestan 



377 



Measurements op Upper Cheek-Tooth No. 1324 



Greatest anteroposterior diameter 



Anteroposterior diameter of protoeone 



24.2 mm. 

 6.2 



NEOHIPPARION OR MERYf'HIPPUS 



A specimen (fig. 2, no. 1323) from beds presumably of 

 Orindan age west of Bolinger Canon is smaller than no. 1324. 

 The protoeone is free to the base, the fossettes seem a little wider 

 transversely and show less marked plications than in the speci- 

 mens tentatively referred to Hipparion. 



This form may represent a species distinct from the other 

 two forms of the Hipparion group or may be included in the 

 genus Merychippus. 



PROTOHIPPlNE( F) ASTRAGALUS 

 An astragalus (fig. 4, no. 9858) from near Bolinger Canon 

 represents a stage of development approximating that of certain 



Fig. 4. Protohippine( ?) astragalus. No. 9858, natural size. Orindan '?, 

 near Bolinger Canon. 



Measurements of Cheek-Tooth No. 1323 



Approximate greatest anteroposterior diameter 



Approximate greatest transverse diameter 



Greatest anteroposterior diameter of protoeone 



18.3 mm. 

 17.7 



5.7 



Miocene horses. The deeply-cut groove of the trochlea is rather 

 narrow, and is markedly oblique. 



