AND GREAT LIGNITE FORMATIONS OF NEBRASKA. 145 
just mentioned, but its posterior margins are not crenated, and the intervening back sur- 
face is more elevated. The apex of the specimen is worn off in a sloping manner an- 
teriorly. This tooth I suspect to represent an incisor. 
As the entire dentition of Megalosaurus has not yet been ascertained, it may turn out 
to be the case, that in other parts of the jaws than those known, it possesses teeth like 
the ones above described as peculiar. Should on future discovery such a condition of things 
be proved to exist, Deinodon would then cease to be any thing more than a second species 
of Megalosaurus. 
As anatomical and geological evidence favour the view that Jywanodon, Trachodon, and 
Hadrosaurus, were amphibious, it is not unlikely that Megalosaurus and Deinodon infested 
the shores, upon which the former quietly grazed or browsed, and proved to them fierce 
and destructive enemies. The two carnivorous saurians perhaps held the same office in 
relation to the more bulky herbivorous lizards, that we find to exist between the larger 
existing feline animals, and the pachyderm solipedal and ruminant mammals. 
Explanation of Figures, Plate 9. 
Figures 21—48, Teeth of DEINODON HORRIDUS; all the size of Nature. 
Figure 21, 7g. Two fragments of a large sabre-shaped tooth; lateral view. 
Figures 22, 23. ‘Transverse sections at the positions marked f. . 
Figure 24. Front view of the same fragments. 
Figure 25. Summit of a sabre-shaped tooth. 
Figure 26. Section at h. 
Figure 27. Summit of another specimen. 
Figure 28. Section at 7. 
Figure 29. Lateral view of the summit of a sabre-shaped tooth, exhibiting the enamel partially worn off. 
Figure 30. Section of the tooth at 7. 
Figure 31. A similar tooth. 
Figure 32. Section at &. 
Figure 33. A small tooth of the same form. 
Figure 34. Section at J. 
Figure 35. Fragment of a large tooth, with its posterior border forming a plane surface as indicated in the sec- 
tion, Figure 36, taken at m. 
Figure 37. Lateral view of the summit of a tooth like the preceding specimen. 
Figure 88. Posterior view of the same specimen. 
Figures 39, 40. Sections at n. o. 
Figure 41. Posterior view of the crown of a tooth, perhaps an incisor. 
Figure 42. Lateral view of the same. 
Figures 43, 44, 45. Sections from the positions indicated. 
Figure 46. Postero-internal view of a conical tooth. 
Figure 47. Antero-external view of the same specimen. 
Figure 48. Section at p. 
