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



to side in its upper part, and compressed from side to side in 

 what I regard as its distal extremity. The posterior border 

 is much more compressed than the anterior border. In the 

 middle length the antero-posterior measurement is If inch 

 and the thickness 1 inch. In the last two inches the anterior 

 border retreats, so that the extremity becomes smaller, though 

 it widens a little from side to side, and terminates in an ovate 

 surface 1£ inch from front to back and about | inch wide. 

 This surface is rough, as though it were cartilaginous and 

 somewhat convex. This chevron-bone is probably from an 

 early caudal vertebra, and helps to give an idea of the great 

 depth of the tail ; for if the neural spine were developed to 

 anything approaching a corresponding length, the vertical 

 depth of the tail would have approached three feet if the spines 

 and processes had been vertical ; but, owing to their oblique 

 direction, it is probable that the depth of the tail did not 

 exceed 18 inches. There are no data for even approximately 

 estimating the length of the tail, since the Pockilopleuron 

 Bucklandi is the only example of a carnivorous type which 

 might be compared. It is, however, probable that the tail 

 was long. 



Late Caudal Vertebra. 



This imperfect vertebra has an elongated form, and when 

 perfect had a length of about 5 inches. It is regarded as 

 caudal from the small size of the neural canal and apparent 

 absence of articular processes for ribs, notwithstanding a 

 certain general resemblance to the early cervical vertebrae of 

 Massospondylus and Zanclodon. 



The neural arch is small and is penetrated back and front 

 by an excavation which has the aspect of a compressed canal 

 above the neural arch, but of smaller size. 



The anterior face of the centrum is lost, together with the 

 pre- and postzygapophyses and the neural spine. The frac- 

 ture shows that the neural canal contracts greatly towards 

 the middle. 



The posterior face of the centrum, imperfectly preserved, is 

 2f inches wide by less than 2 inches deep. The articular 

 surface is concave and has the aspect of being crushed from 

 the underside. 



The base of the centrum contracts in the middle to a width 

 of 1^ inch. It is flattened and rounds convexly into the 

 sides ; those surfaces are somewhat vertical, concave in length, 

 and are margined above by a narrow longitudinal ridge, 

 beneath the middle of which there appears to be a foramen. 

 This lateral ridge is on about the line of junction of the 



