132 REFERENCES TO THE PLATES. 



Figs. 3, 4. Lateral views, a, Crown, on the inner surface invested with enamel ; h, fang, grooved 

 on the inner part for adaptation to the outer border of a succession al tooth ; c, surface, impressed 

 apparently by contact with the side of the apical half of the crown of an infero-lateral succossional 

 tooth ; d, portion of the denticulated enamel border of the crown magnified about six diameters. 



Figs. 5-7. An inferior tooth with the apical half of the crown worn off. 



Fig. 5. Outer view. 



Fig. G. Inner view. 



Fig. t. Lateral view, a, Triturating surface of the crown ; h, cutting edge of the triturating 

 surface. 



Figs. 8, 9. An inferior tooth with the summit of the crown worn off. 



Fig. 8. Outer view. 



Fig. 9. Lateral view. 



Figs. 10-13. A superior unworn tooth, with the greater portion of the fang lest. 



Fig. 10. Outer view of the crown invested with enamel. 



Fig. 11. Inner view. 



Figs. 12, 13. Lateral views, o, Surface impressed by the apical half of the lateral successional 

 teeth ; b, surface impressed by the outside of the apex of the successional tooth above or in the same 

 line ; c, strong carina of the external enamelled surface of the crown. 



Figs. 14-17. A superior tooth with the summit of the crown worn off. References as in the pre- 

 ceding tooth. 



Figs. 18, 19. Ideal representation of the supposed arrangement of the teeth of Iladrosaurus in 

 the relationship of the functional and successional teeth. 



Fig. 18. External view of the relationship of the inferior teeth, a, Triturating surfaces of the 

 teeth; h, teeth with the apical half of the crown worn away; c, tooth with its apex d, worn off; 

 e, tooth worn away to the fang. 



Fig. 19. Internal view of the relationship of the inferior teeth, a, Inner cutting edge of the 

 triturating surfaces ; h, teeth with the apical half of the crown worn away ; c, an unworn tooth ; 

 d, tooth with the crown little more than half developed. 



Figs. 20-23. Mutilated tooth of Adrodon Johnstoni, natural size, from Bladensburg, Md., belong- 

 ing to Dr. C. Johnston. 



Fig. 20. Outer view. 



Fig. 21. Inner view. 



Figs. 22, 23. Lateral views. 



Figs. 24—26. Fragments of the jaws of HadroKaurus, one-half the diameter of the originals. 



Fig. 24. Inner view of a fragment of the lower jaw, exhiliiting the alveolar grooves. 



Fig. 25. Outer view of the same specimen, ninch mutilated. 



Fig. 26. Inner view of a fragment supposed to belong to the upper jaw. 



Figs. 27, 28. Supposed sacro-vertebral body of a young Hadrosaurug, from Monmouth Co., New 

 Jersey, one-half the diameter of the original. 



Fig. 27. Side view. 



Fig. 28. Inferior view. 



PLATE XIV. 



Iladrosaurus FouRii. Bones of the limbs, one-fourth the diameter of the originals. 

 Figs. 1-4. The left humerus. 

 Fig. 1. Posterior view. 

 Fig. 2. Anterior view. 

 Fig. 3. External view. 



Fig. 4. Upper e.xtremitj^ a, Head ; h, internal tuberosity ; c, external tnberosit)^ ; d, deltoid 

 attachment. 



Fig. 5. Anterior view of the left ulna. 

 Fig. 6. Anterior view of the left radius. 



