Prof. H. G. Seeley on Euskelesaurus Brownii. 325 



it does not appear to be in close sutural union with the 

 centrum. The longest centrum is fully 5 inches long on the 

 base and A\ inches along the neural canal, showing that in 

 natural sequence the caudal vertebrae were concave on the 

 superior contour. The posterior face of that centrum is 

 6 inches high. 



The chevron bones in the Jardin des Plantes in some cases 

 are preserved in situ, and in every case the extremity of the 

 bone is imperfect, the longest specimen being only 8 inches 

 long. They are inclined obliquely backward, attached chiefly 

 to the posterior face of the centrum. The bone is compressed 

 from side to side and cleft at the proximal end for 3 inches. 



The transverse width over the fork is 2f inches and the 

 antero-posterior extent is If inch. In front the forked part 

 of the process is flattened ; as it extends distally it becomes 

 rounded. At the distal fracture the bone is f inch thick and 



1^ inch wide. 



The Chevron- Bone. (Fig. 3.) 



Mr. Brown's chevron-bone appears to be 14 inches long ; 

 but it is in two portions, 10-£ and 4\ inches long, and the con- 

 tinuity between them (fig. 3, A A) is not quite certain, though 

 they correspond in size and thickness. 

 The proximal surface is 3£ inches wide, 

 crescentic, fully 1^ inch deep in the middle, 

 convex on the anterior margin, flattened or 

 concave on the posterior margin, and con- 

 cave from side to side. It would appear 

 to have articulated with the hinder margin 

 of the centrum, as in the specimens figured 

 by Mons. Paul Fischer. There appears to 

 have been a transverse connexion of the 

 articular facets of the two sides, in the 

 manner described by Professor Huxley in Chevron-bone of cau- 

 some genera of Dinosaurs ; but a fracture dal vertebra of Eu- 

 having traversed the median line, this 

 condition is not absolutely certain. The 

 V-shaped excavation beneath the articular 

 surface is small in front, not being more than 2^ inches long 

 and less than \ inch wide. On the posterior surface the 

 width appears to be greater. Below the articulation the bone 

 rapidly contracts in width, and in its compressed form, with 

 the parallel anterior and posterior borders, has much the aspect 

 of a costal rib. The anterior convexity in length is most 

 marked towards its lower part. The bone is somewhat flat- 

 tened in front in its middle portion, though convex from side 



skelesaurus Brownii. 

 A A, contact-sur- 

 faces. J* nat. size. 



