PLATE 25 



UPPER MILK TEETH OF PARAHIPPUS, MERYCHIPPUS, PROTOHIPPUS, PLIOHIPPUS, AND HIPPARION. 

 DECIDUOUS PREMOLARS IN DIFFERENT SPECIES OF PARAHIPPUS, MERYCHIPPUS, PROTOHIPPUS, HIPPARION, AND PLIOHIPPUS. 



All figures natural size. 



Pine Ridge, So. Dak. Lower Miocene 1. Parahippus pristinws Osborn, referred specimen, Am. Mus. 12915. 



Primitive stage of Parahippus. 



Niobrara River, Nebr. Pliocene 2. Parahippus cognatus Leidy, type, drawn from cast Am. Mus. 10772. 



Progressive stage of Parahippus. 



Bijou Hills, Missouri River, 3. Mcrychippus insignia Leidy, type, dp 2-3 , (drawn from cast Am. Mus. 



10770, reversed in drawing). Early stage of Mcrychippus. 



Sheep Creek, Sioux Co., Nebr. Middle Miocene 4. Mcrychippus isonesus primus Osborn, referred specimen, Am. Mus. 



14187d. Earliest stage of Merychippus. 



Pawnee Creek, Col. " 5. Merychippus paniensis Cope, referred specimen, Am. Mus. 9413, 



dp 4 , well worn, found in place with m 1-2 and preformed p 4 (re- 

 versed in drawing). 



Snake Creek, Nebr. Lower Pliocene 6. Mcrychippus ?sp., referred specimen, Am. Mus. 14010, dp 1-3 of the 



left side. 



LTpper Pawnee Creek, Col. " 7. Protohippus proplacidus Osborn, type, Am. Mus. 91156, dp^m 1 of 



the left side (reversed in drawing). 



Little White River, So. Dak. " " 8. Profohippus pcrditus Leidy, neotype (Gidley), Am. Mus. 10838, 



dp^m 1 of the left side. 

 9. Iiipparion occidentalc Leidy, referred specimen, Am. Mus. 10579, 

 dp 1 " 4 of the left side. 



Niobrara River, Nebr. " 10. Pliohippus mirabilis Leidy, type, U. S. Nat. Mus. 569, dp 3-4 of the 



right side. 



Little White River, So. Dak. " 11. Pliohippus supremus Leidy, referred specimen, Am. Mus. 10844, 



dp 2 " 4 of the right side. 

 12. Pliohippus pernix Marsh, referred specimen, Am. Mus. 10836, 

 dp^m 1 of the right side. 



Sheep Creek, Sioux Co., Nebr. " 13. Pliohippus intcrpolatus Cope, referred specimen, Am. Mus. 13900a, 



dp 4 of the right side. Progressive stage of Pliohippus. 



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