38 



OSBORN: OLIGOCENE, MIOCENE, PLIOCENE EQUIDiE. 



Characters. — (Osborn, 1904) Molar series somewhat smaller than those of M. bairdii; protoloph and metaloph 

 of nearly equal length; molar crowns short, brachyodont, less elevated than in M. latidens or in M. bairdii; no hypostyle; 

 m 3 of very small size. 



A/O //302 /-/o/otype 

 YaTe AVus 



Mesohippus celer 



Fig. 17. Mesohippus celer Marsh, Yale Mus. 11302, holotype, p 4 -m 3 . Lateral and crown views. Natural size. 



Mesohippus westoni Cope, 1889. 

 Plate 2.10. Text Fig. IS. 



Anchitherium westoni sp. nov., 1 Cope, E. D. "The Vertebrata of the Swift Current River, II," Amer. Naturalist, Vol. XXIII, 

 No. 267, Mar. 1889, p. 153, no figure. "On Vertebrata from the Tertiary and Cretaceous Rocks of the North West Territory. I.— 

 The Species from the Oligocene or Lower Miocene beds of the Cypress Hills," Geol. Surv. of Canada, Contr. to Canadian Palaeontology, 

 Vol. Ill (quarto), Pt. I, 1891, p. 20, PI. xiv, figs. 1, 2, 2a. 



Horizon and locality. — Eastern end of the Cypress Hills, Assiniboia, Canada, at the headwaters of Swift Current 

 Creek, Titanotherium zone. Type collected by T. C. Weston in 1884. 



Fig. 18. (Middle) Original figures of type and cotype of Mesohippus westoni Cope; type (1), Ottawa Mus. 6289, a 

 fractured upper molar, cotype (2, 2a), two doubtfully associated right lower molars, Ottawa Mus. 6313. After Cope, 

 1891, PI. xiv, figs. 1, 2, 2a. (Left) Same teeth redrawn under direction of Osborn. All these figures natural size. (Right) 

 Original figure of additional upper molar (topotype) from the type locality, Ottawa Mus. 6293, collected by Lawrence M. 

 Lambe. After Lambe, 1905, PI. xiv, figs. 1-4. Three-halves natural size. 



x Cope, E. D. "The White River Beds of Swift Current River, Northwest Territory," Amer. Naturalist, Vol. XIX, Feb. 1885, 

 p. 163, listed Anchitherium sp. indet. No figure. 



