DR. MANTELL ON THE IGUANODON. 
201 
and the fang in a great measure absorbed, from the downward growth of a 
successional tooth. 
2. The enamelled and ridged external aspect of the crown. 
2“. The smooth convex inner aspect of the same. 
2*. The abraded coronal surface with its double facets (1 and 2). 
a. Anterior margin. 
b. Posterior marginal angle. 
f. Remains of the fang, showing the cavity produced by a successional 
germ. 
n. Primary ridge. 
Fig. 3. Vertical section of the crown of an unused tooth, seen by transmitted light, 
magnified eight diameters. 
e. Enamel. 
d. Vascular dentine. 
p. Pulp-cavity filled with mineral matter. 
Fig. 4. A successional tooth of the right side of the lower jaw, with the serrated 
coronal margin entire, from Brook Point, Isle of Wight. This specimen is 
identical with the tooth in place (Plate XVL fig. 1), but must have be- 
longed to a larger individual. 
4. The mesial or inner aspect. 
I 
a. The anterior margin. 
b. The posterior marginal angle. 
n. The primary ridge of the enamelled front of the crown. 
4“. The external smooth convex aspect of the same. 
p. Pulp-cavity. 
Fig. 5. A tooth belonging to the left side of the lower jaw; the apex of the crown 
partially worn away. This specimen, together with figs. 1, and 4, with 
numerous vertebrae, a femur 3^ feet long^, and other bones, were obtained 
from the Weald Clay, forming the cliff near Brook Point, Isle of Wight; 
the whole probably belonged to the same individual, which must have been 
an aged reptile of very colossal proportions -f'. 
5. The smooth, convex, outer aspect. 
.5®. Oblique view, showing the posterior side and marginal angle, and the 
ridged enamelled inner surface. 
a. The anterior margin. 
b. The posterior marginal angle. 
f. The fractured extremity of the fang exposing the pulp-cavity {p). 
Fig, 6. Molar of the left side of the lower jaw: in this example the whole of the 
* I have presented this bone to the Hunterian Museum, 
t See my Geology of the Isle of Wight, p. 315. 
