ARCH.EOHIPPUS. 



213 



PROCAMELUS-MERYCHIPPUS CALAMARIUS ZONE. 11. LATE MIDDLE MIOCENE. 



This zone is typified by the Barstow of California and Santa Fe of New Mexico. 



Archaeohippus mourningi Merriam 1913. 

 Text Fig. 173. 



Parahippus (?) mourningi, n. sp., Merriam, John C. "New Anchitheriine Horses from the Great Basin Area," Univ. Cal. Publ. 

 Bull. Dept. Geol. Vol. 7, Xo. 22, Dec. 10, 1913, p. 427, fig. 3. 



5b 



Fig. 173. (3) Original figure of the type of Archceohippus mourningi Merriam, Univ. Cal. Pal. Coll. 19840, dp :i ~ 4 , m 1 . 

 One and one-half natural size. (4) J. ultimus Cope, Univ. Cal. Pal. Coll. 1689, referred upper molar. One and one-half 

 natural size. (5a, 56) Paratvpe of A. mourningi Merriam, Univ. Cal. Pal. Coll. 19704, p 3 -mo. Natural size. After 

 Merriam, 1913, pp. 422, 428." 



Horizon and locality. — Barstow formation, Barstow syneline, Mohave Desert, California. Type collected by H. S. 

 Mourning, Jan. 1913. 



Type. — Univ. Cal. Pal. ("oil. 19840. A portion of a maxillary with milk dentition and m 1 . Measurements: m 1 

 a.p. .0137, tr. .01(5. Paraiype. A portion of a mandible with dentition representing p2-m 2 , Univ. Cal. Pal. Coll. 

 19764. 



Type figure. — Text Fig. 173 of this Memoir. 



Characters. — (Merriam, 1913) (1) Small, brachyodont horse. (2) Metaloph fully united with ectoloph; (3) pro- 

 toloph elongate and lophoid, overlapping left protocone; (4) hypostyle sub triangular; (5) crochet represented by several 

 plate-like projections from outer end of metaloph; (6) cingulum well developed on posterior side; (7) surface of crown 

 somewhat rugose without trace of cement. 



