310 



THE OXFORD OOLITE PERIOD. 



CHAP. 



The largest has a length of 1-45 inch, a breadth of n, and 



m - 



Diagram CXV. Six Caudal Vertebrae of Plesiosaurus Oxoniensis. Scale, one-fifth 

 of nature. The articular surfaces biconcave, and rather pitted in the middle. 



height (to the canal) 1-5; in the smallest the measures are, length, 

 0*85; breadth, rs; height to the canal, 0*90. 



Pelvic girdle. The materials for describing this part of the 

 skeleton are complete in respect of the pubic and ischial bones, 

 which, though never found together in the way represented in 

 Diagram CXVL, were probably so arranged in the living animal. 



Diagram CXVI. Pelvic Girdle of Plesiosaurus Oxoniensis. Scale, one-tenth 



of nature. 



P. Pubis. 



I. Ischium. 



F. Femur. 



The shapes of both these bones are somewhat peculiar, and it is 

 only after long and frequent consideration and comparison with 

 remains of other plesiosaurians, and skeletons of recent turtles, that 

 the arrangement in the woodcut was adopted. The anterior portion 

 of the pubis, incomplete in the middle parts, is supplied by general 



