196 



osborn: OLTGOCENE, MIOCENE, PLIOCENE EQTJID.E. 



long and nearly straight as in Hipparion occidental)?; (3) in its present worn condition little external cement; (4) outlines 

 of the lakes [fossettes] not extended inward as in H. occidentale and transverse diameters relatively small; (5) anterior 

 lake [prefossette] with one posterior inflection, one interior and one anterior inferior; (6) posterior lakes [postfossette] two 



Fig. 159. Type of Hipparion sinclairi Wortman, Amer. Mus. 8178. (Left) Original figure of the type, after Cope, 1S89, 

 figs. 2, 2a, p. 458. (Three right-hand figures) Drawings of type under the direction of Osborn by S. Oka; crown, interior, 

 and anterior views. Crown in original figure is drawn at an oblique angle to the grinding surface. All figures natural size. 



anterior inflections, one interior and one posterior, a short loop extends toward the inner 

 column area; (7) the latter [protocone] convex on the outer side and without trace of 

 angle or apex. (8) (Gidley) The type upper molar presents the characters of the genus 

 Neohipparion; (9) somewhat larger than the type of H. montezuma Leidy; (10) differs 

 from that species in the relatively larger and differently formed protocone and the more 

 simple enamel plications; (11) inner face of protocone of II. sinclairi slightly concave as 

 in H. affinc. 



Hipparion molle Merriam 1915. 

 Text Fig. 160. 



Neohipparion molle, n. sp., Merriam, John C. "New Species of the Hipparion Group from 

 the Pacific Coast and Great Basin Provinces of North America," Univ. Cal. Publ. Bull. Dept. Geol, 

 Vol. 9, No. 1, June 29, 1915, p. 3, fig. 2. 



Horizon and locality. — From the lower Jaeahtos, North Coalinga region, California. 

 Lower Pliocene. Type collected by T. H. Ruckman. 



Type. — Univ. Cal. Pal. Coll. 21370, an upper molar of the left side, m 3 . Measure- 

 ments: (Merriam) m 3 a.p. .0193 approx.; tr. 0158 approx.; a. p. diameter of protocone 

 .0094, length of crown .048. 



Type fig arc— Text Fig. 160 of this Memoir. 



Character*. — (Merriam, 1915) (1) Characterized by the length and narrowness of the 

 upper cheek teeth ; (2) simplicity of the enamel borders of the transversely narrow pre- and 

 postf ossettes ; (3) unusually long anteroposterior diameter of the laterally compressed 

 protocone. (4) Of much smaller size than the type of H. mohavense, fossettes relatively 

 narrow, walls of the fossettes showing less plication. (5) Resembling the type of //. montezuma Leidy in general dimensions. 



Merriam (1915, p. 3) observes that the type of //. molle shows resemblances to the type of H. montezuma Leidy, of 

 Hidalgo, Mexico, also to the type of //. .sinclairi Wortman of the Rattlesnake Pliocene of eastern Oregon. 



Fig. 160. Original figure 

 of Jthe type of Hipparion 

 molle Merriam, Univ. Cal. 

 Pal. Coll. 21370, third 

 superior molar of the left 

 side. Inner view and 

 cross section at the point 

 indicated by S. Natural 

 size. After Merriam, 1915, 

 fig. 2, p. 2. 



