REFERENCES TO THE PLATES. 131 



exposed by fracture and loss of portion of the tooth ; e, vasculo-neural foramen in the outer parapet 

 of the jaw. 



Fig. 5 Fragment of a pterygoid bone with a penultimate tooth, inner view, from Monmouth 

 County, New Jersey. The tooth resembles the corresponding one in the specimen represented in 

 Pig. 1. a, Cavity for the successional tooth. 



Fig. 6. Fragment of a lower jaw, inner view, from Monmouth County, New Jersey, a, Tooth, the 

 fang of which is coossified with its alveolus ; h, successional cavity ; c, fang of the tooth in advance, 

 the crown having been shed ; d, fully developed crown of a successor included within its cavity ; e, 

 cavity for a successional tooth ; f, portion of a vacant alveolus. 



Fig. 7. Outer view of the successional tooth removed from the preceding specimen. 



Fig. 8. Fragment of a lower jaw, inner view, from Monmouth County, New Jersey. The inner wall 

 of the jaw was removed by accident, and exposes the fangs of the teeth, successional cavities, and 

 dental canal, a, Remains of a fang coossified with its alveolus, and deeply excavated for the recep- 

 tion of a successional tooth ; h, tooth in advance, the crown broken off, the fang entire and loose in 

 its socket, from which it may be lifted out; c, cavity for a successional tooth ; d, fang firmly coossified 

 with its socket, and deeply excavated into a cavity containing a successor ; e, fang of a tooth loose 

 in its socket. 



Fig. 9. Outer view of the successional tooth seen in place in the preceding specimen. 



Fig. 10. Inner view of a tooth, with a small portion of the jaw, from Monmouth County, New 

 Jersey, belonging to the collection of Mr. Willis, a, Exserted portion of the fang; 6, inserted portion 

 coossified with its socket ; c, cavity for a successor. 



Fig. 11. Inner view of a successional tooth, from Marlboro, Monmouth County, New Jersey, 

 belonging to Rutgers College. It is totally devoid of subdivisional planes. 



Fig. 12. Crown of a tooth, broken from its fang, outer view, from Monmouth County. It exhibits 

 only the faintest trace of subdivisional planes. 



Fig. 13. Anterior extremity of the right side of the lower jaw, external view, half the diameter of 

 nature. From Freehold, Monmouth County, New Jersey. From Dr. Thompson's collection. 



Fig. 14. Pterygoid bone, with teeth, inner view. Specimen obtained in Mississippi, and belonging 

 to Dr. Spillman. Holcodus ? 



Fig. 15. Crown of a tooth of Mosasaurus, inner view, from Burlington County, New Jersey. An 

 acute ridge exists alone along its concave border. 



PLATE XII. 



Vertebras of Hadrosaurus Foulkii, one-third the diameter of the original specimens. 



Figs. 1-3. Cervical vertebrae. Left lateral view. The side of the specimen of Fig. 1 is mutilated 

 by a large excavation. That of Fig. 2 is less mutilated in the same manner. That of Fig. 3 is 

 broken at the posterior inferior part. 



Fig. 4. An anterior dorsal vertebra. Left lateral view. 



Pig. 4, a. Posterior view of the same specimen. 



Pigs. 5-8. Dorsal vertebrae from the middle of the series. 



Figs. 9, 10. Anterior caudal vertebrae. 



Pigs. 11-16. Middle caudal vertebrre. 



Figs. lT-20. Posterior caudal vertebrae. 



Fig. 20, a. End view of Fig. IT. 



PLATE XIII. 



Pigs. 1-19. Teeth of Hadrosaurus Foulkii, of the natural size. 

 Figs. 1-4. A nearly perfect unworn inferior tooth. 

 Fig. 1. Inner view. 

 Pig. 2. Outer view. 



