1870.] HANCOCK AND HOWSE—MARL-SLATE PROTEROSAURI. 567: 
longitudinal radiating strie. The upper extremity of some of the 
anterior spinous processes are strongly roughened at the sides, as if 
for muscular attachment. 
The anterior zygapophyses are stout and well produced ; they in- 
cline outwards and upwards. The posterior pair are considerably 
shorter than the anterior, and stretch backwards or outwards to 
overlap them. 
The transverse processes are not well preserved ; but distinct traces 
of them are observed in most of the vertebree, and on one or two 
the form is pretty well seen. They are simple, short, and obtuse, 
and are lengthened a little in the direction of the long axis of the 
centrum. 
The caudal vertebre are longer in proportion to their height 
than those of the trunk; and the neural arch, as in them, is com- 
pletely united to the body, no suture or other trace of the junction of 
the parts being perceptible. The spinous process is as long propor- 
tionately, and those near the root of the tail are of the same shape 
as those of the trunk. But further down they become considerably 
contracted at the base in the direction of the long axis, and gra- 
dually widen in the same place upwards. The spine of the last 
joint on the slab, being the fifteenth or sixteenth of the tail, exhibits 
at the upper margin an indication of the peculiar bifurcation of the: 
lower distal caudal spines of this saurian. 
The anterior zygapophyses are considerably longer than those of 
the trunk-vertebre, and are more inclined upwards. Immediately 
beneath the neural arch on either side of the centrum there is a 
longitudinal ridge, which, near the centre of the body, is produced 
a little into a short projecting tubercle, the transverse process. The 
ehevron bones forming the hemal arch are about as long as the 
dorsal spine, but are much narrower, and are of a spatulate form, 
being narrower at the proximal and flat and small towards the 
outer extremity. They are not fixed, like the processes, in con- 
nexion with the neural arch, but are articulated below to the broad 
reflected margin of the posterior extremity of the body, articulated, 
as it were, between the joints, and are inclined backwards. Only a 
few of them remain, but two or three are well displayed on a frag- 
ment of the counter-slab, which has fortunately been preserved. 
The lumbar vertebre are not well marked, and in this region the 
specimen is unluckily fractured. Certainly two, perhaps three, of 
the last vertebre of the trunk are, however, apparently anchylosed. 
Von Meyer seems to have been uncertain whether there were two or 
three pelvic joints; but from what he states it would seem hkely 
that three is the number. 
A fragment of a flattened rounded bone, measuring 13 inch across, 
lies directly below the lumbar vertebra. This is probably a portion 
of the pelvic girdle, and is the only indication of its presence. This 
resembles in form the rounded extremity of a bone (tab. iv. f. 1, 2, 
of von Meyer’s work) lying in contact with the femur, and is pro- 
bably a portion of either the pubis or ischium. 
Immediately in front of the fragment lie the short ribs, which are 
