214 DESCRIPTION OF REPTILES. 
mences at the fore-part of the conjoined epizygapophyses, 27, and the diverging 
ridges, np, fig. 3, are continued directly from the back part of its base ; not from 
a little in advance of this, as in Python, n p, fig. 6. The neural spine in Paleophis 
is also longer than it is represented in the figure 3 (as I have ascertained by ver- 
tebre subsequently discovered), and proportionally longer therefore than in Py- 
thon. The anterior views of the corresponding vertebre of Paleophis (fig. 1) and 
Python (fig. 4) show the characteristic differences in the transverse extent of the 
prezygapophyses, z e, and the shorter diapophyses, d, which are sessile in Python, 
but subpedunculate in Paleophis. The posterior views, figs. 2 & 5, show the still 
more striking difference in the form of the back-part of the platform or basis of 
the neural spine (ns), which is quadrate in Paleophis, but triangular in Python 
and all known existing serpents. 
In the inferior transverse extent of the prezygapophyses, ze, and zygapophy- 
ses, se’, of the Paleophis, we may discern a minor degree of deviation from the 
Lacertian type than in modern serpents ; but in the genus of Lacertians (Iguana), 
which makes the nearest approach to the typical Ophidians by the presence of 
upper articular processes or epizygapophyses in addition to the normal ones at 
both ends of the neural arch, such accessory processes are distinguishable in the 
Iguana by their smaller relative size and their closer approximation to the in- 
ferior and normal zygapophyses: the diapophyses are also smaller and more 
elevated in the Iguana than in the Paleophis. 
On comparing together eighteen paleophidian vertebra of different sizes from 
Bracklesham, the smallest being of the dimensions represented in figs. 7 & 8, and 
Fig. 7. Fig. 8. thence gradually increasing to the size of the speci- 
men figs. 1, 2 & 3, I find the following differences : 
in fig. 8, e. g. the articular cup and ball at the ends 
of the centrum are larger in proportion to the length 
of the centrum, as compared with the next-sized 
vertebra, fig. 7: the under surface of fig. 8 is convex 
transversely between the diapophyses, and sends 
down a short median ridge: in fig. 7 it is concave 
4 
Palcophis Paleophis 2 the same part, and without the median ridge ; but 
Typhaus? porcatus? — both vertebrae have the median process (hypapophysis) 
at the back-part of the under surface. In fig. 7 the fore-part of the epizygapo- 
physes is concave, in fig. 8 it is flat; in fig. 7 the upper border is straight, in 
fig. 8 it forms an open angle: the space between the epizygapophyses and pre- 
zygapophyses is greater in fig. 7 than in fig. 8. 
