SAUROPODOUS DINOSAUKS FEOM THE WEALDEN. 18t) 



Museum (no. II. 1616), which it was suggested might belong to the 

 same species as the teeth. Of this vertebra two views are given in 

 PI. IX. figs. 1, la; and it will be seen from these figures that 

 this specimen comprises the greater part of the centrum, with the 

 exception of the anterior ball. The base of the neural canal still 

 remains, but the surfaces for the articulation of the neural arch arc 

 destroyed. From the circumstance that the neural arch is lost, it 

 is highly probable that the specimen is not fully adult; but the 

 smooth outer surface of the bone indicates that it did not belong to 

 a very young individual, being, in this respect, very widely different 

 from the vertebra) from the Kimeridge Clay, described by Sir Owen 

 as Bothriospondylus suffossus, which Prof. Marsh suggests may have 

 belonged to a foetal Dinosaur. I take it, then, that this vertebra 

 indicates a comparatively small Dinosaur, and since it evidently be- 

 longs to the suborder Sauropoda, there is a strong presumption that 

 it belongs to the same form as the above-mentioned teeth. When I 

 say the same form I would, however, guard myself by adding that 

 it is quite likely the teeth may indicate more than a. single species. 

 Comi)ared with the figure of the dorsal vertebra of the typical 

 P. nanus, it will be seen that this specimen agrees in the great depth 

 of the posterior cup, and also (allowing for the loss of the anterior 

 ball) in the comparative length of the centrum, and in the large size 

 and shelving upper portion of the lateral cavity. Compared with 

 the large dorsal of Hoplosaurus (OrnitJiopsis), figured by Mr. Hulke 

 in vol. xxxvi. pi. iv. of the Society's Journal, the greater propor- 

 tionate length of the centrum and the larger size and more sloping- 

 boundaries of the lateral cavity are very noticeable in the present 

 specimen. The approximate length of the entire centrum was pro- 

 bably some three inches, against 3'8 inches in the typical dorsal of 

 P. nanus. So far therefore as I can see, the provisional reference 

 of the Wealden teeth to Pleuroccelus is confirmed by this specimen, 

 which appears to differ from the dorsal vertebrae of the type form 

 by features of merely specific value. 



The second specimen I have to notice is a somewhat larger im- 

 perfect vertebra, obtained from the Wealden of Brook in the Isle of 

 Wight, and till recently preserved in the Dorsetshire County 

 Museum at Dorchester. This specimen is represented from the left 

 lateral and anterior aspects in PI. IX. figs. 2, 2 (c. It is a dorsal 

 vertebra, evidently referable to the Sauropoda, and, from the com- 

 plete union of the arch with the centrum, clearly belonging to a 

 fully adult individual. The neural arch is preserved in fair con- 

 dition, as high up as the platform from which the transverse pro- 

 cesses took their origin ; and the union between the arch and 

 centrum is so intimate that even the neuro-central suture cannot be 

 detected, although its approximate position is indicated in the figure. 

 The centrum has lost its lower half, the horizontal fracture extending 

 through the plane of the central pit of the lateral cavity. The im- 

 perfect upper portion of the anterior articular ball remains, but the 

 contour of the posterior cup has been entirely destroyed. The outer 

 lamina of bone on the upper part of the sides of the centrum has 



Q.J.G.S. No. 182. 



