300 
DR. MANTELL ON THE OSTEOLOGY OF 
of the Iguanodon, but the bodies are relatively broader and flatter, and not so much 
pinched up beneath the intervertebral notches ; but a reference to the Plate will furnish 
a better idea of these differences than can be conveyed in words. 
Since the observations on which the above remarks are chiefly founded were 
made, Dr. Mantell has informed me, that according to the account given by the 
fisherman who collected the cervical, anterior and middle dorsal, first sacral, and 
anterior caudal vertebrae — all of which I had assigned to the Iguanodon — they were 
found not only in the same limited area, but in such collocation as to give rise to the 
conviction in the mind of one who had certainly no theory to support, that they con- 
stituted portions of the same ‘ backbone,’ and were associated with bones of the 
hinder extremity of the Iguanodon of proportionate size, now in Dr. Mantell’s Col- 
lection, and partly described in this memoir. Although unwilling to lay any undue 
stress on this circumstance, it will, we conceive, raise in the minds of future ob- 
servers such presumptive evidence in favour of the opinions here advanced, as may, 
independently of the mere intrinsic value of the argument from analogy, lead them to 
view favourably our proposed restoration of thewertebral column of the Iguanodon. 
The time is perhaps not far distant, when the exertions of the many collectors of 
the Wealden fossils will yield the materials for continuing these interesting researches, 
and modifying or confirming our conclusions. And, although, we feel it is difl&cult 
to convey to the minds of others that conviction of their accordance with nature, 
which has been impressed on our own after the repeated examination of a more ex- 
tensive and instructive series of specimens than has, perhaps, fallen under the observa- 
tion of any other palaeontologists, we may be permitted meanwhile to indulge the 
hope that a step has been taken in the right direction, to reconstruct the skeleton of 
the marvellous Reptilian Herbivore, whose earliest known remains were first exhumed 
from the Wealden formation of Sussex, during the infancy of Palaeontology. 
Description of the Plates. 
PLATE XXVI. 
Sacrum of the Iguanodon; in the Collection ofW. D. Saull, Esg., F.G.S. 
(One-half linear, the natural size.) 
Figs. 1, 2, 3, 4, 5, 6. The six anchylosed vertebrae composing the Sacrum ; 1, is the 
first or most anterior vertebra. 
a'. Anterior articulating facet. 
a”. Posterior . 
h. Sacral ribs. 
h'. Confluence of the sacral ribs at the outer extremity of the left side. 
h". Sacral foramina. 
* Expansion of bone from the rib across a sacral foramen. 
