234 



BR. A. S. WOODWARD ON THE 



[Apr. 18, 



anterior vertebra is deeply opisthocoelous, and the anterior two- 

 tliivds of the uppei- half of its lateral face are impressed on each 

 side with a shallow ovoid cavity, which has a gently rounded (not 

 sharp-edged) margin. The centrum supposed to represent a 

 middle dorsal vertebra is slightly smaller, and the ovoid depression 

 in the upper half of its lateral face is more extended antero- 

 posteriorly. Neither specimen exhibits any hollowing of the 

 lower face. A posterior dorsal vertebra, which seems to be the 

 last and in direct contact with the sacrum, is represented not only 

 by its centi-um but also by the greater part of the neural arch 

 text-fig. 40). It is remai-kably shortened, the centrum being still 



Text-fis-. 40. 



Cetiosai 



'•us leedsi. — Posterior dorsal vertebra, laelving neural spine ; posterior and 

 (A) right lateral aspects, ss., zygospliene. About j nat. size. 



about as wide as deep, but its length somewhat less than half the 

 extreme diameter. This centrum is much constricted, and the 

 shallow depiession in the upper part of its latei'al face disappears 

 at the base of the neui'al arch. Its anterior face is not well pre- 

 served, but seems to have been slightly convex; while its posterior 

 face is only gently and irregulaily hollowed, as if it had been 

 originally capped by cartilage. The neural canal is ovoid in 

 section, and much deeper than wide. The deep and laterally- 

 compressed zygospliene [zs.) is prominent. An isolated neural 

 spine, which probably belongs to a dorsal vertebi^a, is latei'ally 

 compressed and short, with a truncated and somewhat hollowed 

 apex ; there are no bony laminae or ridges on its lateral face, but 

 a pair of laminfe extend down its postero- lateral edges and expand 

 below into the prominent triangular zygapophyses. 



