PROTOHIPPUS. 



139 



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



Characters. — (Merriam, 1915, Osborn, 1918) (1) Protocone and hypocone in the same longitudinal plane; (2) 

 from the crochet region a pli caballin, a prominent crochet fold projecting into the prefossette; (3) a prominent fold pro- 

 jecting into the postfossette; (4) pre- and postfossettes triangular in form. 



Fig. 110. Original figures of the juvenile type of Protohippus pachyops Cope, Geol. Surv. Texas Coll. (cast Amer. 

 Mus. 14394). After Cope, (1892) 1893. (A) Crown view of inferior molars, PI. ix, fig. 3. Natural size. (B) Side 

 view of portion of the skull, PI. iii, fig. 1. One-half natural size. (C) Crown view of superior milk molars, PI. ix, fig. 2. 

 Natural size. 



Protohippus proplacidus sp. nov. 



Plates 25.7, 34.3. Text Fig. 112. 



Horizon and locality. — Sand Canon, head of Pawnee Creek, Logan County, Colorado, Upper Pawnee Creek beds, 

 Procamelus-Hipparion zone, Lower Pliocene. Type collected by Barnum Brown of the American Museum expedition of 

 1898. Paratypes also from Sand Canon. 



