. Oeological Society. 61 



The Trilobite was found by Robert E. Jones and Robert Lloyd, 

 two quarrymcR, at Bethesda. Afterwards Prof. Debbie found a 

 detached head of the same species near the spot where the original 

 was obtained. The Author desired to return thanks to Prof. J. 

 Dobbie, of the University College of ^orth Wales, Bangor, for the 

 opportunity of describing these specimens. 



2. " On Theco^pondylus Daviesi, Seeley, with some Remarks on 

 the Classification of the Dinosauria." By Prof. H. G. Seeley, 

 P.R.S., E.G.S. 



The Author desci'ibed 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 Coehinis, Marsh. The 

 only European genus hitherto described in which the vertebrgo are 

 similarly elongated, compressed, and enveloped in a dense external 

 film of bone is that indicated by the sacrum, named Thecospondylus 

 Horneri, whose vertebrae are about 11 centimetres long, whilst the 

 cervical vertebras now under discussion were 9 centimetres long 

 when complete. The specimen has lost the prezygapophj'ses and 

 cervical ribs. If these were restored they would probably approxi- 

 mate in shape to those of Coeliirus frag'dis. 



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 indi- 

 cates the points of difference. In estimating the resemblance to 

 Thecosjiondijlus he regards the thinness of the investing layer of 

 bone, the smoothness of its internal surface, the elongation and 

 lateral compression of the vertebrse, and a certain general approxi- 

 mation in form : the most remarkable difii'erence is the absence from 

 the cast of Thecospondijlas Horneri of indications of films of bone, or 

 evidence of internal plates, such as are seen in the present specimen. 

 The Author observed that Prof. Marsh regards Coelurus fragiUs as a 

 generalized Sauropsid, with more resemblance to Dinosaurs than to 

 Pterodactyles. 



Professor Marsh has formed an Order, Sauropoda, which includes 

 Cetioscmrus and Ornithopsis. The Author remarked 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 Ccelurus is grouped, it becomes necessary, in order to deter- 

 mine the systematic position of Thecospondylus, to review its rela- 

 tions. The Author would unite Saurop jda with Theropoda into one 

 Order, the Saurischia, whose pneumatic skeleton is an approximation 

 towards Ornithosaurs and Birds. 



