AN AUSTRALIAN SAUROPTERYOIAN — ETHERIDGE. 
25 
The centra in these vertebra? are decidedly short, more propor- 
tionately so than in Cimoliosaurus can tabridgiensis, Lydk.,* * * § and 
in this respect approach nearer to those of C. valdensis, Lydk.,f 
and C. cnrymerus , Phill. J 'There is not- the slightest* appearance 
of any rugosity round the edges of the terminal faces of the centra 
as in Plesiosaurus rugasas , Owen,§ from the Lias, but they are 
prominent and outwardly bevelled as in C. cautabridyiensis \ nor 
is there any sinuous profile with overhang of the upper border, 
and prominence of the lower border of the centra as in the genus 
Polyptychodon . The sides of the centra can hardly be described 
as concave, although the ventral surfaces are fairly soon either side 
the haemal carina. 'The anterior and posterior articular surfaces 
vary in contour from circular to subquadrafce, the transverse dia- 
meter being always the greater, with a well marked although not 
thick border, surrounding a wide and fairly deep concavity or 
cup. There are no mammilla), or any trace of a pit in the vertebra? 
examined. The venous or lnemal foramina are situated in definite 
depressions, well marked and deep, and in the best preserved 
vertebra No. 1, (PI. v., Fig. 4) three-sixteenths of an inch apart, 
this being the transverse measurement of the haemal carina. The 
latter expands fore and aft in buttress formation into the anterior 
and posterior peripheries of the terminal faces, producing on the 
whole an hour-glass shaped figure, as in C. nmstriclus, Owen. 
The single costal facets are rarely seen in consequence of the 
thorough union that lias taken place between the head of the ribs 
and the costal surface itself. In one, however (No. 2), where the 
head of the rib appears to have broken out, the pit or scar seems 
to ho circular. The fore and aft borders of the neurapophyses 
are vertically concave, the fore much more so than the hind, and 
transversely are more angular than convex, particularly posteriorly. 
The neuro-central suture is almost totally obliterated. Xygopo- 
physial ridges, the prominent lateral oblique ridges extending from 
the pre-zygopophyses to the posterior borders of the pedicle, can 
hardly bo said to exist. The pre-zygopophyses are rather high, 
and in the only vertebra in which they are sufficiently preserved 
No. 1, (PI. v., Fig. 5), do not project forward beyond the vertical 
line of the terminal face of the centrum, not even as much as in 
G. wldemis, Lydk., and G. limnophilus, Kokon.|| The zygopo- 
physial articular surfaces approach the oval in form, and are very 
obliquely inclined, much more so than in either the last-named 
species, C. cantabridgiensis , or G. eurymerus. The post-zygo- 
pophyses are not preserved in the most perfect vertebra of the 
* Oat. Foss. Reptilia and Amphibia Brit. Mus., pt. ii., 1889, p. 183, f. 60. 
f [bid, p. 188, f. 61. 
t Lydekker, ibid, p. 206, f. 67. 
§ Mon. Foss. Reptilia Liassie Formations, pt. i., 1865, p. 35. 
|1 Leydkker, loc. cit., p. 225, f. 69. 
