EXPLANATION OF THE PLATES. (j5 



PLATE XIU. 



Megalonyx Jeffeusonii. Tliu liguics arc all ouc-balf the diamcti'i- of nature, ami are from speci- 

 mens in Dr. Owen's collection. 



Fig. L Dorsal view of the right external cuneiform bone. 



Fig. 2. Its distal articular surface, for the third metatarsal hone. 



Fig. 3. Its proximal view, presenting a large articular surface, on the left of the ligure, for the sca- 

 phoid bone, and a small one to the right for the cuboid bone. 



Fig. 4. Dorsal view of the right cuboid bone. 



Fig. 5. Articular surface of the same specimen, for the last two metatarsal bones. The figure should 

 have been turned with the concave border to the right, so as to correspond with figures H* and 16. 



Fig. 6. The cuboid bone articulating with the fourth metatarsal bone, and e.xhibiting an articular 

 surface, which joins the external cuneiform and scaphoid bones, and the astragalus. 



Fig. 7. The scaphoid bone, exhibiting the articular surface for the astragalus, and part of tiiat for 

 the cuboid bone. 



Fig. 8. Distal view of the same bone, exhibiting articular surfaces for two cuneiform bones. 



Fig. 9. Inner view of the second metatarsal bone. 



Fig. 10. Outer view of its proximal extremity. 



Fig. IL Tarsal view of the same specimen. . 



Fig. 12. Dorsal view of the fourth metatarsal bone. 



Fig. 13. Inner view of the fourth metatarsal bone. 



Fig. 14. Outer view of the fourth metatarsal bone. 



Fig. 14*. Tarsal view of the fourth metatarsal bone. 



Fig. 15. Dorsal view of the fifth metatarsal bone. 



Fig. 16. Tarsal view of the fifth metatarsal bone. 



Figs. 14* and 16 have inadvertently been drawn upside down. i^ 



Fig. 17. Homologuc of the first and second phalanges of the median toe ; lateral view. 



Fig. 18. Tipper view of the same specimen. 



Fig. 19. Lateral view of the median ungual phalanx. 



Fig. 20. Upper view of the median ungual phalanx. 



Fig. 21. Lateral view of the ungual jihalanx, either of the second or of the fourlli toe. 



PLATE X I \. 



Mylodon Haklani. Figs. 1, 2. Upper and outer views of a fragment of the right .side of the lower 

 jaw, containing all the teeth except the first one. Two-thirds the diumcter of nature. From a speci- 

 men found at Big-bone-lick, Kentucky, and now belonging to the New York Lyceum of Natural History. 



Fig. 3. Posterior view of a right humerus, one-third the diameter of nature. The specimen is con- 

 tained in the cabinet of the Academy of Natural Sciences, and was found at Big-bonc-lick, Ken. 



Megalonyx dissimilis. The figures are of the natural size, and are from specimens, in Dr. Dickc- 

 son's collection, found near Natchez, Mississippi. 

 . Fig. 4. Outer view of a first inferior molar tooth of the left side. 



Fig. 5. Triturating surface of the same specimen. 



Fig. 6. Marginal view of the same siiccinien. 



Fig. 7. Anterior view of a last upper molar tooth. 



Fig. 8. Triturating surface of the same specimen. 



Ereptodon priscus. The figures of the natural size, and taken from a specimen, in Dr. Dickeson's 

 collection, from near Natchez, Mississippi. 



Fig. 9. Side view of a molar tooth. 



Fig. 10. Triturating surface of the same specimen. 



Fig. 11. Marginal view of the same specimen. 

 9 



