1919] Merriam: Tertiary Mammalian Faunas of Mohave Desert 577 



external faces are flatter than in M. proprius, but do not show the 

 suggestion of median longitudinal ribs seen in M. buwaleli. P* shows 

 approximately the form seen in M. buwaldi. P 3 seems slightly more 

 advanced, and P 2 is decidedly more progressive than in M. proprius 

 or M. 'buwaldi. In P 2 the diameter of the crown is greater trans- 

 versely and the anterior pocket is much larger. 



The upper canine is possibly a little smaller than in M. proprius 

 compared with the size of the skull. It is somewhat larger relative to 

 the size of the skull than in Pronomotherium altiramuin. 



214 215 



Fig. 214. Meryooahoerus? (Pronomotherium?) calif ornicus? , n. sp. M 1 and 

 M 2 , no. 21353, X %. Kicarclo Pliocene, Mohave Desert, California. 



Fig. 215. Merycoohoerus? (Pronomotherium?) calif ornicus?, n. sp. Symphy- 

 sis of mandible, no. 21567, X %. Eicardo Pliocene, Mohave Desert, California. 



Measurements of Skull, no. 21351 



Width across occipital region including expansion of mas- 

 toid plates 175 mm. 



Height of inion above upper border of foramen magnum .... a92 



Width of palate between inner borders of M 2 74 



Width of posterior narial opening between processes 49 



Height of zygomatic arch immediately below orbit 45 



a, approximate. 



Measurements of Dentition 



Length of upper molar-premolar series, no. 21351 and no. 



23128 combined 167.5 mm. 



Length of premolar series, no. 23128 63.5 



Length of molar series, no. 21351 ol04 



No. 23128 



Anteroposterior diameter of superior canine at base 14.3 



P 2 , anteroposterior diameter 16.5 



P 2 , greatest transverse diameter 13.5 



P 3 , anteroposterior diameter 16 



P 3 , transverse diameter 17.2 



P 4 , anteroposterior diameter 16 



P 4 , transverse diameter 21.1 



a, approximate. 



