122 University of California Publications in Geology [Vol. 10 



Measurements 



No. 21780 



M 1 ?, anteroposterior diameter 19.1 mm. 



M 1 ?, transverse diameter 17.7 



M 1 ?, anteroposterior diameter of protoeone 6.4 



No. 21781 



M-, anteroposterior diameter 17.8 mm. 



M-, transverse diameter at middle height of crown al6.5 



M=, anteroposterior diameter of protoeone 6.1 



No. 21782 



P 1 , anteroposterior diameter 18.8 mm. 



P 1 , transverse diameter 18.0 



I' 1 , anteroposterior diameter of protoeone 6.6 



No. 21784 



Pj, anteroposterior diameter 20.3 mm. 



Pi, transverse diameter all.l 



P-„ anteroposterior diameter of metaconid-metastylid column 12.9 



No. 21785 



M.r 2 , anteroposterior diameter 19.3 mm. 



Mj, transverse diameter 9.5 



Mi, anteroposterior diameter of metaconid-metastylid column 11.3 



a, approximate. 



LIMB FEAGMENTS OF NEOHIPPAEION 



Two fragments of small metapodials represent an eqnid form not 

 larger than the smallest species of Merychippus of the Barstow Mio- 

 cene. Specimen 22365 (fig. 10), the proximal end of a small slender 

 metacarpal three, possesses a narrow shaft suggesting that of the 

 small Barstow Merychippus. The position of the unciform facet is, 

 however, quite different from that in all of the many Barstow speci- 

 mens examined by the writer. In the Barstow forms the unciform 

 facet cuts that of the magnum at an angle ranging betwen 112 and 

 121.5 degrees. In the Ricardo horses, so far as known, the correspond- 

 ing angle ranges between 128 and 131 degrees, and the unciform facet 

 approaches distinctly nearer to the plane of the magnum facet than 

 in the Barstow forms. In no. 22365 from the Tejon Hills the magnum- 

 unciform angle is 131 degrees, as in the Ricardo horses. 



A second metapodial specimen, no. 22376 (fig. 11) represents 

 the distal end of a small metapodial of approximately the size shown 

 in no. 22365. In this specimen the median keel is strongly developed 

 on the posterior side but, as in the small Barstow Merychippus, it 

 tends to fade out in the proximal region of the anterior side. In the 

 Ricardo horses the keel is more strongly expressed. 



In a fragmentary specimen representing a proximal phalanx, no. 

 22375 (fig. 13) the groove for reception of the distal keel of the meta- 



