Correspondence—Prof. H. G. Seeley. 45 
specimen was obtained. The author desires to return thanks to 
Prof. J. Dobbie, of the University College of North Wales, Bangor, 
for the opportunity of describing these specimens. 
4. “On Thecospondylus Daviesi, Seeley, with some Remarks on the 
Classification of the Dinosauria.” By Prof. H. G. Seeley, F.R.S., 
E.G.S. 
The author described the anterior third of a vertebra from the 
Wealden, which was recognized by Mr. Davies as the cervical 
vertebra of an animal allied to the genus Celurus, Marsh. The 
only Huropean genus hitherto described in which the vertebrae are 
similarly elongated, compressed, and enveloped in a dense external 
film of bone is that indicated by the sacrum, named Thecospondylus 
Horneri, whose vertebre are about 11 centimetres long, whilst the 
cervical vertebrae now under discussion were 9 centimetres long 
when complete. The specimen has lost the prezygapophyses and 
cervical ribs. If these were restored, they would probably approxi- 
mate in shape to those of Celurus fragilis. 
The author gave an outline-restoration. The points of resemblance 
were chiefly the elongated form, lateral compression of centrum and 
neural arch, inclined articular face of centrum, mode of attachment 
of the ribs, the convex external surface of the neural arch, almost 
total suppression of the neural spine, and the thin texture of the 
bone. But this affinity does not amount to generic identity, and he 
indicates the points of difference. In estimating the resemblance to 
Thecospondylus he regards the thinness of the investing layer of 
bone, the smoothness of its internal surface, and the elongation and 
lateral compression of the vertebrae, and a certain general approxi- 
mation in form; the most remarkable difference is the absence from 
the cast of Thecospondylus Horneri of indications of films of bone, or 
evidence of internal plates, such as are seen in the present specimen. 
He observed that Prof. Marsh regards Celurus fragilis as a generalized 
Sauropsid, with more resemblance to Dinosaurs than to Pterodactyles. 
Professor Marsh has formed an Order, Sanropoda, which includes 
Cetiosaurus and Ornithopsis. The author remarks that he had already 
suggested Cetiosauria as separable from the rest of the Dinosaurs. 
When an additional Order is instituted for animals with cavernous or 
pneumatic vertebrae, the Theropoda of Marsh, under which Celurus 
is grouped, it becomes necessary, in order to determine the systematic 
position of Thecospondylus, to review its relations. The author would 
unite Sauropoda with Theropoda into one Order, the Saurischia, 
whose pneumatic skeleton is an approximation towards Ornithosaurs 
and Birds. 
CORRESPONDENCE. 
—— 
CLASSIFICATION OF THE DINOSAURIA. 
Srr,—Will you allow me to state that I did not forward to the 
_GeotoctcaL MaGazine the abstracts of my British Association papers 
printed in the December Number, pp. 561-563, and that no proof of 
those abstracts was submitted to me; so that I am not responsible 
