1915] 



Merriam: New Species of the Hipparion Group 



3 



N EOHIPP ARION MOLLE, n. sp. 



Type specimen, an upper molar, no. 21370, from the Jacalitos formation of 

 the North Coalinga region, California. This species is characterized by length 

 and narrowness of the upper cheek-teeth, simplicity of the enamel borders of 

 the narrow fossettes, and unusually long anteroposterior diameter of the laterally 

 compressed protocone. 



Compared with specimens of Hipparion mohavense from the 

 Ricardo Pliocene, the tooth crown in N. molle is smaller, the fossettes 

 are relatively narrow, and the walls of the fossettes show less plication. 

 The protocone of the Jacalitos species is absolutely wider anteropos- 

 terior]^ and much narrower transversely. 



The form represented by specimen no. 21370 (fig. 2) resembles 

 Neoliipparion montezumae described by Leidy from Lacaultipan. 

 Hidalgo, Mexico, in general dimensions. In the type specimen of 

 N. montezumae the borders of the fossettes are more complicated while 

 the protocone is not as wide anteroposterior^ and is relatively less 

 compressed laterally than in the Coalinga form. Better material of 

 both the Mexican and the Coalinga forms may show closer relationship 

 or even identity of the two. N. sinclairii of the Rattlesnake Pliocene 

 in eastern Oregon is of the same general type as N. montezumae and 

 N. molle. 



Measurements of Type Specimen 



M 3 , anteroposterior diameter 



M 3 , transverse diameter 



M\ anteroposterior diameter of protocone 



M 3 , length of crown 



a, approximate. 



NEOHIPPARION LEPTODE, n. sp. 



Type specimen, a lower molar, no. 19414, Thousand Creek Beds, Thousand 

 Creek, Nevada. Crown much elongated, slender, relatively straight, well ce- 

 mented, much compressed laterally. Metaconid-metastylid column long antero- 

 posteriorly, narrow transversely, with wide, flat internal groove. Hypoeonid ridge 

 prominent. A strong external protoconid ridge present. 



Specimen 19414 (fig. 3) from locality 1101 in the Thousand Creek 

 region resembles in many respects the peculiar Equus eurystylus de- 

 scribed by Cope 1 from the Goodnight? Beds of Paloduro Canon, Texas. 

 Gidley 2 considers the horizon at which this fauna was found as upper 



1 Cope, E. P., Geol. Surv. Texas, 3rd Ann. Rep. for 1891, p. 43, pi. 12, figs. 

 7-8, pi. 20, fig. 6. Issued 1892. 



2 Gidley, J. W., Bull. Am. Mus. Nat. Hist., vol. 19, p. 632, 1903. 



rtl 9.3 mm. 

 015.8 

 9.4 

 48 



