566 “PROCEEDINGS OF THE GEOLOGICAL SOCIETY. [June 8, 
expense of much labour and judgment. One is the remains of a 
well-developed individual; but little more than vertebrae and a few 
of the ribs in a more or less dilapidated state are preserved; but on 
another slab three or four perfect ribs have occurred. The other 
specimen is in a much more perfect condition, the principal bones 
of three of the limbs being well displayed as well as one of the fore 
feet and most of the ribs, which le in regular order on either side 
of the vertebral column. The former, as already mentioned, is 
undoubtedly the remains of Proterosaurus Speneri, and the latter a 
new species of the same genus, Proterosaurus Hualeyi. 
PROTEROSAURUS SPENERI, v. Meyer. (Pl. XX XIX.) 
The bones of the specimen of this species are in a very perfect 
condition, the surface of them being quite intact, and in places having 
‘even a semigloss. The vertebre are lying articulated in a much 
curved line, the animal having apparently died with the spine 
arched violently backwards, as seems to have been the case with all 
the examples hitherto obtained. In our specimen the curve is even 
more sharp than usual, the remains of the column forming almost 
half a circle. The anterior portion of it is thrown suddenly back, 
and.at the pelvic region it is as suddenly bent upwards. 
In all there are thirty-five or thirty-six vertebre and casts of 
vertebree in continuous order, measuring, if placed in a right line, 
22 inches in length. Of these vertebrae twenty-one appear to be- 
long to the trunk, and fifteen or sixteen are caudal. Now if we 
deduct two or three for the lumbar vertebre, there will remain 
seventeen or eighteen dorsal vertebre. Meyer concluded, after 
carefully enumerating the joints in all the known individuals, that 
the number is “not under sixteen, and not over nineteen ;” so that 
it would appear that the whole of the dorsal vertebre are present, 
in front only the cervical being deficient. As Meyer estimates the 
tail-joints at more than hn -six or thirty-eight, it would then 
appear that more than half of them are wanting in the specimen 
before us. 
The centrum of the dorsal vertebree is upwards of ? inch long, 
and about 3 inch in height. In one of the largest “pogans figured 
by von Meyer (tab. ix.) it is Zinch long and 2 “inch high. It would 
therefore seem that the Midderidge example is full-grown and a large 
individual. It is impossible to “observe the ends of the vertebree, 
as they are all articulated; but from the appearance of the joints 
where they gape a little, it would seem that both the anterior and 
posterior articular surfaces are slightly concave, and their margins 
appear as if reflected ; the sides of the centrum are smooth and are 
a little concave. 
The spinous process is 17 inch high, being more than twice the 
height of the centrum, and it is 4 an inch from back to front; con- 
sequently it is considerably shorter than the body. It is much 
compressed, and is expanded a little above in the direction of the 
long axis of the vertebre ; and the dorsal margin or crest is slightly 
arched in the same direction, and exhibits on the sides delicate 
