252 
PROFESSOR H. G. SEELEY OY THE STRUCTURE, ORGAYIZATIOR, 
The locality from which the specimen was obtained is unkDOWD, but the bones 
correspond in size with the cervical vertebrae already described, il'hree vertebrae in 
the middle of the series are fairly well preserved. 
The centrum is 1‘7 centim. long, very slightly concave from back to front, with 
the ai’ticular margins moderately elevated. From side to side the external surface is 
well rounded, and the transverse diameter is 2 centims.; towards the neuro-central 
suture the diameter contracts to about half as much in the middle. The vertical 
depth of the articular face exceeds 1‘5 centim.; it is conically excavated. 
The neural arch is defined from the centrum by a transverse sutui’e. It is high, 
rises along the whole length of the centrum, extends oblicpiely outward, so that this 
concavity forms a continued depression with the upper part of the centrum. Both 
anterior and posterior surfaces rise steeply, so as to form at the interlocking of two 
neural arches a circular foramen for the inter-vertebral nerve, which is given off high 
above the centrum, on a level with the transverse processes, so that its summit is fully 
1'6 centim. above the neuro-central suture, and its diameter about 6 millims. The 
anterior border is concave between the base and the middle of the pre-zygapophysis, 
which, does not extend in advance of the centrum, and has its facet looking inward. 
The superior, inferior, anterior, and posterior sides of the lateral part of the neural 
arch converge outward in a pyramid, and the angularities between them are lost in 
the rounded transverse process, which extends outward and a little backward for 
1'5 centim. beyond the pre-zygap»ophysis, and terminates in a flattened facet for the 
single-headed rib. 
The neural spine is inclined backward in position, so as to extend above the inter¬ 
vertebral foramen. It is prolonged ujoward and a little backward; is 1 centim. wide 
from front to back, though the measurement may be slightly more towards the Tree 
end, where it is imperfect; but its height from the inter-vertebral foramen exceeds 
3 centims. The spine is compressed from side to side, and convex from front to back, 
so that the anterior and posterior margins are sharp. The post-zygapopliyses appa¬ 
rently have an articular facet posteriorly, as well as laterally; the former is immedi- 
diately above the middle of the transverse process. 
The fragments of ribs on the other side of the slab are about 12 centims. long, 
curved, more than half a centimetre in diameter, and cylindrical. 
In the large slab already referred to, as indicating the extent of the dorsal region, 
there are only seven dorsal riljs exposed ; and I infer, from the absence of ribs in the 
lumbar region, that three or four vertebrae anterior to the sacrum may in some 
specimens have been without ribs, though other larger fossils appear to have the ribs 
extending to the sacrum. 
