202 
DR. MANTELL ON THE IGUANODON. 
serrated part of the crown is worn away, and the fang absorbed by the 
pressure of a successional tooth. 
6. The smooth convex outer aspect ; the worn surface of the crown has 
two distinct facets, as in the abraded coronal planes of figs. 3 and 4. 
6“. The inner or mesial aspect of the same. 
PLATE XIX. 
A portion of the anterior part of the left upper maxillary bone of an adult Igua- 
nodon, from Tilgate Forest: represented of the size of the original*. 
Fig. I. The inferior or alveolar aspect, showing the remains of the sockets of ten 
molars. 
f,f. Dental alveoli. 
X. The intermaxillary articulating surface. 
Fig. II. The upper or nasal surface, with deep channels for the infra-orbital vessels 
and nerves. 
a, a. The infra-orbital canal. 
h. Retrograde furrow of the same. 
c. A deep concavity in the roof of the infra-orbital canal (see description, 
ante, p. 191). 
X. The anterior marginal surface that articulated with the intermaxillary 
bone. 
* This specimen is in the British Museum. 
The nearly perfect tooth figured in Philosophical Transactions, 1841, Plate VI. figs. 1, 2, 3, is an upper 
molar of a very young Iguanodon. Fig. 4 of the same plate is the coronal germ of an upper tooth. 
