1870. ] HULKE—-WEALDEN VERTEBRA. 319 
The centrum has unfortunately been broken across, and the greater 
part of it, including both articular faces, is missing. Only a small 
part of it, including the floor of the neural canal, remains, sur- 
mounted by a singularly framed superstructure, which, although 
much distorted by pressure, is yet sufficiently preserved to afford a 
good idea of its perfect form. 
The bony tissue is very compact, which makes the outer surface 
very smooth, and even polished. It takes principally the shape of 
thin plates, many of which are not thicker than stout writing-paper. 
Where the interior of the stouter parts of the vertebra is exposed, 
the broken surfaces show a thin outer shell of bone enclosing an 
extremely coarse cancellated tissue, the spaces of which are immense, 
exceeding by many times those of the cancellous tissue of all the 
contemporary Dinosaurs yet known to us, and reminding us in some 
measure of those of Pterodactylian bones. 
The neurapophyses (Pl. XXII. figs. 1 & 2, np), in their present 
mutilated state, measure about 5 inches from front to back; but their 
real length was greater, for they have suffered by the compression of 
the back of the vertebra. How far they descended on the sides of the 
centrum is not determinable; but their present height measures 
about 5 inches from the floor of the neural canal to the level of its 
crown; and from that to the level of the root of the neural spine is 
nearly 1 inch more. Their anterior margin is stout, their posterior 
margin thinner; and intermediately their substance is reduced to a 
very thin lamina, the outer surface of which is strengthened by a series 
of minor buttresses and arches projecting in high relief. The greater 
stoutness of their anterior margin has reference to the support of 
the large preezygapophyses. 
These latter articular processes (prz) project directly forwards in 
front of the neural spine, and they overhang the entrance of the 
neural canal (nc). ‘Their anterior inferior angle is borne by a stout 
buttress which springs from the front of the neurapophysis. They 
have two articular surfaces :—-a larger upper one, of a flat, oblong, 
tabular form, at the level of the base of the neural spine (the crown 
of the arch), directed upwards and slightly inwards, for articulation 
with the corresponding large oblong face of the postzygapophysis ; 
and asmaller subtriangular articular surface directed inwards towards 
the middle line, forming the sides of a notch separating the two 
preezygapophyses (figs. 1&3, ). This notch is nearly 2 inches deep 
from front to back. Its width is -7 inch behind, and about 1:3 inch 
in front. 
The postzygapophyses (fig. 4, psz) lie directly under the posterior 
pillars of the neural spine (to be presently described). Their size 
and shape correspond to those of the prazygapophyses; and their 
direction is the reverse, viz. downwards and slightly outwards. No 
notch intervenes between them as between the anterior articular pro- 
cesses; but their inner borders coalesce in the middle line, and from 
their junction a stout plate (fig. 4, w) descends vertically to the crown 
of the neural canal—in other words, to the summit of the neural arch. 
This plate measures nearly 2 inches vertically, and it is -9 inch thick. 
