50 



OSBORN : OLIGOCENE, MIOCENE, PLIOCENE EQTJIDiE. 



The name eulophus was assigned (Osborn, 1904, p. 173) in reference to the relatively perfect or continuous and unin- 

 terrupted condition of the transverse crests. The species was regarded as apparently ancestral to Miohippus meteulophus 

 of the Leptauchenia zone and to Hypohippus of the Miocene. Matthew (1915) regards this as probably a subspecies or 

 geographical variation of Mesohippus bairdii. 



Colodon copei Osborn and Wortman, 1895. 



Mesohippus copei, sp. nov., Osborn, H. F., and Wortman, J. L. " Perissodactyls of the Lower Miocene White River Beds," Bull. 

 Amer. Mus. Nat. Hist. Vol. VII, Art. XII, Dec. 23, 1895, pp. 356-358, fig. 5. 



Horizon and Locality. — Badlands near Cheyenne River, Protoceras zone, South Dakota. Type collected by American 

 Museum Expedition, 1894. 



Type. — Amer. Mus. 1197, a pelvis (also erroneously associated femur, tibia, and part of hind foot). The pelvis, 

 the bone first mentioned belongs to some species of rhinoceros or lophiodon and is not that of a horse. The association 



Fig. 29. Type of Mesohippus eulophus Osborn, Am. Mus. 8791. (K) Original figure of left maxilla of type, con- 

 taining p L m 3 . Natural size. After Osborn, 1904, fig. 5, p. 174. (6) Side view of type skull, partly reversed in drawing. 

 One-half natural size. 



of the other bones proves to have been erroneous. The femur does not belong with the pelvis. The identification of the 

 tibia and astragalus has not been made; both bones are equine, however, and may be provisionally compared with Mio- 

 kippus crassicuspis. 



The premolars, Am. Mus. GS3, provisionally referred to this species by Osborn and Wortman (1895, p. 357, fig. 5) 

 do not belong to the genus Colodon but represent a large equine with interrupted crests, renamed Miohippus 

 crassicuspis by Osborn in 1904. 



