42 



osborn: OLIGOCENE, MIOCENE, PLIOCENE EQUID.E. 



and metalophs which are continued to the ectoloph, and are very little divided, thus resembling those of M. culophus; 

 (4) the external cingulum sweeps upward across the parastyle instead of rising with it. The cotype lower teeth p 2 to 

 m 3 measure 79 mm., indicating an animal of large size." 



Mesohippus proteu lophus 



Upper 77 r a nor fieri u m 



A/o s/4-a 7ype (reisJ 

 A . M. 



L/p/jer Vitanotneri urn 



Mesoh ippus proteuloprius 



Fig. 23. (2) Type of Mesohippus proteulophus Osborn, Amer. Mus. 514a, p 4 -m 2 . Natural size. (1) Amer. Mus. 

 1208, a referred specimen. One-half natural size. Both figures reversed in drawing. 



Mesohippus prsecocidens Lambe, 1905. 

 Text Fig. 24(14). 



Mesohippus prcecocidens, sp. nov., Lambe, Lawrence M. "Fossil Horses of the Oligocene of the Cypress Hills, Assiniboia," Trans. 

 Roy. Soc. Canada, 2nd Ser., Vol. XI, Sec. IV, 1905-1906, issued Aug. 1905, p. 46, PI. ii, fig. 2. 



Horizon and locality. — Oligocene deposits capping the Cypress Hills, Assiniboia, Titanotherium zone to Leptauchenia 

 zone. This type is regarded (Lambe) as of Titanotherium zone age. Type collected by Lambe. 



74- 



20. 



,33 



m 



18 



br. 



ml- 



Fig. 24. Original figures of Lambe's types of Mesohippus from the Cypress Hills, Assiniboia, Canada. Reproduced 

 direct from Lambe's original drawings of his type figures. All figures natural size. After Lambe, 1905-1906, PI. ii, figs. 

 2-6, 6a, 6b, 7, 8, 8a, 8b. 



(14) Crown view of type of Mesohippus prwcocidcns Lambe, Ottawa Mus. 6297, left upper molar. Lambe, PI. ii, 



fig. 2. 



(15) Crown view of cotype of M. propinquus Lambe, Ottawa Mus. 6290, nr of the left side. Lambe, pl. ii, fig. 3. 



(16) Crown view of upper premolar referred to M. propinquus Lambe, Ottawa Mus. Lambe, PI. ii, fig. 4. 



(17) Crown view of upper premolar, Ottawa Mus., referred to M . brachysiylus Osborn. Lambe, PI. ii, fig. 5. 



(18, 19, 20) Type of Mesohippus stcnolophus Lambe, Ottawa Mus. 6302, an upper molar. (18) Crown view, (19) 

 anterior aspect, (20) exterior view. Lambe, PI. ii, figs. 6, 6a, 6b. 



(21) Crown view of type of Mesohippus planidens Lambe, Ottawa Mus. 6304, m 1-2 . Lambe, PI. ii, fig. 7. 



(22, 23, 24) Crown view of type of Mesohippus assiniboicnsis Lambe, Ottawa Mus. 6305, p 2 . (23) External aspect of 

 same, (24) posterior aspect of same. Lambe, Pl. ii, figs. 8, Sa, 8b. 



