112 



OSBORN: OLIGOCENE, MIOCENE, PLIOCENE EQUIDiE. 



Gidley (1907) regarded this as close to the type of M. labrosus. Matthew (1915) regards it as pointing toward the 

 Protohippus perditus type. The series of referred specimens give good comparative age characters and individual 

 variation. 



Fig. 85a. Merychippus sejunctus Cope, Amer. Mus. 8291. Skull of the type. One-half natural size. Drawn 

 by B. Yoshihara under the direction of Osborn. 



Merychippus sphenodus Cope, 1889. 



Plates 10.2, 12, 15.1,2,3, 18.4, 43.1, 47.2, 48.3, 53.1. Text Fig. 87. 



Hippotherium sphenodus Cope, Cope, E. D. "A Review of the North American Species of Hippotherium," Proc. Amer. Philos. 

 Soc. Vol. XXVI, 1889 (sig. dated June 5, 1889), p. 449, no figure. 



Horizon and locality. — (Cope) " Two superior molars of this species were obtained by me in the same locality as that 

 furnishing the H. paniense [the Loup Fork beds of northeastern Colorado] and at the same time. Several years later I 

 obtained two other molars from the same place, viz., the Pawnee Buttes of N. E. Colorado." Type collected by Edward 

 D. Cope. (Osborn, 1918) The type of M. .sphenodus is more progressive and appears to belong to a higher geologic level 

 than the cotype. 



Type, cotype, and neotype. — "Specimen No. 1." Type. Crown of the second upper premolar, p 2 of the right side. 

 Amer. Mus. Cope Coll. 8281. [Cope at this time (1889) was using the reverse enumeration of the premolars, hence the 

 "third premolar" of his description (op. eit. p. 450) is really the second premolar, p 2 .] Measurements: (Cope, Specimen 

 No. 1) p 2 longitudinal .018; anteroposterior .025, transverse at column .019. Cotype. A left superior premolar, p 3 of the 

 left side, of another individual, Amer. Mus. Cope Coll. 8281. Measurements: (Cope) longitudinal .015, anteroposterior 

 .022, transverse .021. Neotype (Osborn). Amer. Mus. 1291. 



Type figure. — 15.2, text Fig. 87 of this Memoir. 



Referred specimens in the American Museum collections are Nos. 8251, 9390, 9400, 9408. 



