462 REFERENCES TO THE PLATES. 



Fig, 9. Upper view of the same specimen, n, iw.sition of tlio incisors; i, canine; '■, fir.st premolar; 

 </, c, second and third premohirs. 



PLATE XVI. 



Elotheeium Mortoni. See page 175. 



View of the restored skull, represented from a -number of fragments belonging to individuals of 

 different ages and sizes. Two-thirds the diameter of nature. 



The fragments o, /', '• are from the same individual, which had not yet reached maturity. The 

 specimens are represented in PI. VIII, Fig. 1, PI. IX, Figs. 1, 2, and PI. X, Figs. 6, 7, of the Ancient 

 Fauna of Nebraska. The upper portion of i is restored from another specimen. The fragment </ is 

 from a third specimen, and has the end of the nasals restored from the same one as the upper portion 

 o?h. The fragments c/ are from a fourth individual, and are partially restored from specimens be- 

 longing to two other individuals. 



PLATE XVII. 



All the figures are of the natural size. 

 Figs. 1, 2. Peotohippus peeditus. See page 275. 

 Fig. 1. Portion of the right maxilla, containing the posterior four molars. 

 Fig. 3. Triturating surfaces of these teeth. 

 Figs. 3-7. Merychippus insignis. See page 296. 



Fig. 3. Fragment of the right maxilla, containing the first and second temporary molars. 

 Fig. 4. View of the triturating surfaces of the same teeth. 



Fig. 5. Triturating surfaces of a series of upper permanent molars of the right side. 

 Fig. 6. A first upper molar of the left side of the permanent set. 

 Fig. 7. A fourth or fifth molar of the same side. 

 Figs. 8-15. Meeychippus mieabilis. See page 299. 

 Fig. 8. Portion of the right maxilla, with the posterior four molars. 

 Fig. 9. Triturating surfaces of the same teeth. 



Fig. 10. Portion of the right maxilla, containing the second and third temporary molars. 

 Fig. 11. Triturating surfaces of the latter teeth. 



Fig. 12. Second permanent molar from the interior of the specimen represented in fig. 10. 

 Fig. 13. Outer view of the same tooth. 



Fig. 14. (Inadvertently indicated as being in plate A, on page 299.) Triturating surfaces of the 

 first and second right upper molars of the temporary series. 

 Fig. 15. A first upper permanent molar of the right side. 



PLATE XVIII. 



Views of the triturating surface of upper molar teeth of various equine animals. Figures all of the 

 natural size. Specimens from the Niobrara River except when mentioned otherwise. 



Figs. 1-5. HippAEiON occiDENTALE. See page 281. All the teeth from the same individual. 

 Specimens from the Mauvaises Terres of White River. 



Fig. 1. Fifth molar of the right side. 



Fig. 2. Fourth do. The specimen imperfect, and represented as restored. 



Figs. 3, 4. Second and first molars. 



