166 



OSBORN: OLIGOCENE, MIOCENE, PLIOCENE EQUID/E. 



Horizon and locality. — Lower Etchegoin, ten miles north of Coalinga, California. Type from locality 2073. The 

 faunal zone near the base of Etchegoin in the North Coalinga region represents a distinctly more advanced stage than 

 that of the Jacalitos. Name of collector not given. 



Type. — Univ. Cal. Pal. Coll. 21341. A fourth superior premolar, p 4 , of the right side. Measurements: (Mer- 

 riam, 1915) p 4 a.p. .0272, tr. .0244, height of crown .053. 



Type figure. — Text Fig. 133 of this Memoir. 



Characters. — (Merriam, 1914, 1915) (1) Type belonging to an animal of medium size, approaching in dimensions 



Fig. 133. Original figures of the type of Pliohippus coalingensis Merriam, Univ. Calif. Pal. Coll. 21341, p 4 . Natural 

 size. Fig. 29a Cross section of tooth at point indicated by s on fig. 296; fig. 29b outer view. After Merriam, 1915, p. 230. 



Pliohippus supremus. (2) Differs from P. supremus in the heavier mesostyle, relative narrowness (in transverse diameter) 

 of the crown even toward the base, narrower fossettes, much less plicated enamel walls of fossettes, much smaller, 

 more nearly circular protocone. (3) Resembles P. fairbanksi of the Ricardo approximately in size, in simplicity of 

 fossettes, in the very small, round protocone, and weak connection of the protoloph and metaloph; (4) differs from 

 P. fairbanksi in the narrower and less curved crown of the molar teeth, the narrowness being apparently a normal char- 

 acter of worn teeth; (5) possibly separated only by subspecific characters from P. fairbanksi. (6) A larger and more 

 progressive stage than the Pliohippus or Protohippus species of the Jacalitos. 



