EXPLANATION OF PLATE XXXIII. 



All the figures of the natural size. 



Figs. 1, 2. Equus occidentalis : 



Fig. 1. The anterior four upper molars of the left side, seen on their triturating surfaces. 



The teeth are contained in a jaw-fragment, ohtained by Dr. George H. Horn from an 



asphaltum deposit near Buena Vista Lake, California. Specimen in the museum of the 



Academy of Philadelphia. 

 Fig. 2. A second upper left molar, seen on the triturating surface. From Tuolumne County 



California. 



Figs. 3-18. Equus major: 



Figs. 3, 4. A first upper molar tooth of the right side. Fig. 3. Outer view. Fig. 4. Tritu- 

 rating surface. Specimen from Hardin County, Texas. 



Figs. 5, 6. A first upper molar of the right side. Fig. 5. Outer view. Fig. 6. Triturating 

 surface. " From Illinois Bluffs, Missouri. 



Figs. 7, 8. A last upper molar of the right side. Fig. 7. Outer view. Fig. 8. Triturating 

 surface. From Hardin County, Texas. 



Fig. 9. A last lower molar of the left side, view of the triturating surface. Found with the 

 last. 



Fig. 10. A fifth lower molar of the left side, triturating surface. Found with the last. 



Fig. 11. A second or third upper molar of the right side, triturating surface. From Galves- 

 ton Bay, Texas. Presented to the Academy by Dr. Thomas H. Streets. 



Fig. 12. A first lower temporary molar, triturating surface. From Hardin County, Texas. 



Fig. 13. An upper last temporary molar of the left side. Found with the last. 



Fig. 14. An upper second or third molar of the left side. From the "phosphate beds" of 

 Ashley Eiver, South Carolina. 



Fig. 15. A second or third lower molar of the right side. From the same locality as the last. 



Fig. 16. An upper second or third molar of the right side. From Luzerne County, Pennsyl- 

 vania. 



Fig. 17. A second lower molar of the left side. Found with the last. 



Fig. 18. An upper fourth or fifth molar of the left side. From Texas. 



Fig. 19. Equus. Portion of an upper molar of the left side of an undetermined species. From the lignite 

 beds of Shoalwater Bay, Washington Territory. 



Figs. 20, 21. Two phalanges of undetermined animals, both found, in association with the equine and 

 other remains, in an asphaltum deposit in Hardin County, Texas. They are both satu- 

 rated with bitumen. Fig. 20. Lateral view of the specimen. Fig. 21. Inferior view of 

 the second specimen. 



