356 



THE PORTLAND OOLITE PERIOD. 



CHAP. 



magnitude and proportions suited to the others already mentioned. 

 Nearly circular in section, and contracted in the middle of its 

 otherwise cylindrical short body, it looks like a broad pulley wheel. 

 The articulating faces are subtruncate above, the anterior one least 

 concave ; the edges rugose, not reflected. 



1 2 



Diagram CL. Pleiosaurus macromerus. Scale one-fifth of nature. 

 I. Dorsal vertebra, seen sideways. 2. The same, viewed from above. 



Length, 4/3 inches; breadth, 7-1 ; height to edge of canal, 6-9. 

 If length be taken at 100, breadth = 168, height = 164. 



A caudal vertebra, found in the gravel of St. Giles's, Oxford, 



Diagram CLI. Pleiosaurus macromerus. Scale one-fifth of nature. 

 i. Caudal vertebra, seen on the left side. a. The same, viewed from below. 



is mentioned by Professor Owen in his Report on Fossil Reptiles 



