MERYCHIPPUS. 



121 



crowns often equal approximately to twice their width. Protocone round, tending toward circular form in cross-section, 

 and discrete up to a stage of very advanced wear. Enamel bordering the fossettes commonly more complicated than in 

 any of the larger Merychippus forms of the Barstow Miocene." 



This species includes the smallest members of the Merychippus series in the Barstow Miocene. 



Merychippus intermontanus Merriam 1915. 

 Text Fig. 95. 



Merychippus intermontanus, n. sp., Merriam, J. C. "New Horses from the Miocene and Pliocene of California," Univ. Cat. Publ. 

 Bull. Dept. Geol. Vol. 9, Nov. 4, Nov. 22, 1915, pp. 50-52, fig. 2, 3. 



Horizon and locality. — Barstow, Barstow formation, Upper Merychippus zone, Upper Miocene, Mohave Desert, Cali- 

 fornia. From Locality 1401. Name of collector not given. 



Type. — Univ. Cal. Pal. Coll. 21400. Complete superior molar series of right side, p 2 -m 3 . Measurements: premolar- 

 molar series, p 2 -m 3 .146; p 4 a.p. .0249, tr. .921; m 1 a.p. .024, tr. .0217. 



Type figure. — Text Fig. 95 of this Memoir. 



Fig. 95. Original figures of the type of Merychippus intermontanus Merriam, Univ. Cal. Pal. Coll. 21400, p 2 -m 3 . 

 After Merriam, 1915; crown view, fig. 2, p. 51, outer view of in 2 , fig. 3, p. 51. Natural size. 



Characters — (Merriam, p. 50) "Cheek-teeth large; crowns long, strongly curved, heavily cemented. Protocone 

 of upper cheek-teeth uniting early with protoconule. Enamel walls bordering the fossettes comparatively simple." 



Merriam (p. 50) distinguishes the type of this species from that of M. calamarius by its larger size, longer crowns, 

 heavier cementation, and more pronounced tendency toward union of the protocone and protoconule even in young 

 individuals; also in its closer approach to the Protohippus type. It is distinguished from Protohippus by the presence 

 of less cement on the molar crowns in a number of referred specimens. 



Merychippus californicus Merriam 1915. 

 Text Fig. 96. 



Merychippus californicus, n. sp., Merriam, John C. "Tertiary Vertebrate Faunas of the North Coalinga Region of California, 

 a Contribution to the Study of Palaeontologic Correlation in the Great Basin and Pacific Coast Provinces," Trans. Amer. Philos. Soc. 

 N. S. Vol. XXII, Pt. Ill, 1915, p. 197, figs. 3a, 3b, 3c, 3d. 



Horizon and locality. — From Merychippus zone between typical "Temblor" and "Big Blue," north Coalinga region, 

 Fresno County, California. Type collected by Chester Stock and C. L. Moody. 



