PLATE 13 



UPPER TEETH OF MERYCHIPPUS FROM MONTANA, OREGON, AND NEBRASKA. 

 COMPARISON OF VARIOUS SPECIES FROM MIDDLE MIOCENE FORMATIONS OF THE WESTERN UNITED STATES. 



All figures natural size. 



Maseall, Ore. Middle Miocene 1. Mcrychippus isoncsus Cope, type, Am. Mus. 8175. 



Deep River, Mont. " " 2. M . isoncsus Cope, referred specimen, Am. Mus. 8105. Upper teeth, much 



worn. 



Sheep Creek, Sioux " " 3, 3a. M. isoncsus primus Osborn, type, Am. Mus. 14187. Teeth little worn. 



Co., Nebr. 3, Crown view, 3a, outer view of m 3 . 



" " " 4. M. isoncsus secundus Osborn, type, Am. Mus. 14179. Teeth less than half 



worn (partly reversed in drawing). 

 " " " 5, 5a. M. isonesus tcrtius Osborn, type, Am. Mus. 14180. Teeth half worn. 



5, Crown view, 5a, outer view of m 3 . 

 " " " 6. M. isonesus fertius Osborn, referred specimen, Am. Mus. 14183. Teeth much 



worn. (Reversed in drawing). 

 " " 7, 7a. M. isoncsus quintus Osborn, type, Am. Mus. 14185. Teeth little worn. 



. 7, Crown view, 7a, outer view of m 3 . 

 Maseall, John Day Middle Miocene 8. Merychippus seversus Cope, type, Amer. Mus. 8180. Upper molar, little 



Basin, Ore. worn (reversed in drawing). 



Maseall (?) "Oregon " 9. Mcrychippus rclictus Cope, type, Amer. Mus. 8673. Upper molar, about 



Desert " half worn. 



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