184 ON REMAINS OF SMALL SAUROrODOUS DINOSAURS. 



also been more or less completely destroyed, so that the contour of 

 the shelving superior half of the lateral cavity has been lost. In the 

 figure an approximate restoration of the lower half of the centrum 

 has been made from comparison with the preceding specimen. 



So far as its imperfect condition admits of comparison, the contour 

 of the portion of the centrum now remaining appears to be very 

 similar to that of the preceding specimen, the upper half of the 

 lateral cavity having the same shelving form, while its central fora- 

 men was small and clearly defined. Moreover, when entire, the 

 centrum must evidently have been of an elongated type, its approxi- 

 mate length being about four inches. There is accordingly no 

 apparent reason why this specimen should not have belonged to an 

 adalt individual of the same species as the one to which the preceding 

 vertebra pertained ; although I would not deny that we may have 

 to do with two distinct but allied species. 



In the absence, however, of any evidence in favour of a contrary 

 view, I propose to refer both these specimens provisionally to 

 Pleurocoelus valdensis. Their especial interest lies in the circum- 

 stance that, in conjunction with the above-mentioned teeth, they 

 afford absolutely conclusive evidence of the occurrence in the English 

 Wealden of a diminutive Sauropodous Dinosaur, which was the con- 

 temporary of the huge Hoplosaurus, and the still more gigantic 

 Pelorosaurus ; and they also serve to increase the evidence as to the 

 similarity of the Dinosaurian fauna of the Upper Jurassic of North 

 America to that of the Upper Jurassic and Lower Cretaceous of 

 Europe. 



EXPLANATION OF PLATE IX. 



Vertebrae from the Wealden ; referred to Pleurocaelus valdensis. 



a, lateral cavity of centrum ; b, anterior ball of centrum ; c, posterior 

 cup of centrum ; d, neural canal. 



Fig. 1, 1 a. Left lateral and posterior aspects of the imperfect centrum of an 

 immature dorsal vertebra, vpith a restoration of the anterior ball ; 

 from Cuckfield, Sussex. | nat. size. (Brit. Mus. no. E.. 1616.) 

 2, 2 a. Left lateral and anterior aspects of an imperfect dorsal vertebra, 

 with a restoration of the lower half of the centrum ; from the Isle 

 of Wight. ^ nat. size. (Brit. Mus. no. E. 1730.) 



