102 
PL ESI OX A UR I A FROM THE 
NOTE ON THE VERTEBRAE OF TWO SPECIES OF 
PLIOSAURUS. 
Pliosaurus brachyspondylus. 
In his additional notes on Ichthyosaurus and Plesiosaurus, 
Yol. i. Series 2, Transactions of the Geological Society , Mr Cony- 
beare figured certain vertebrae (pi. 22) three inches in diameter, 
which in his paper on Plesiosaurus dolichodeirus were referred to 
the Market-Raisin fossil at Oxford, and named P. giganteus. 
Mr Conybeare thus recognised it as a Pliosaur, but it probably 
ought not to have been referred to a species to which Prof. Owen’s 
descriptions assign cervical vertebrae having a diameter of 5 or 
6 inches. 
Prof. Owen refers to the same vertebrae as evidence of his 
Plesiosaurus brachyspondylus, but they are Plesiosaur in that 
general sense only in which Pliosaur itself may be so named. 
The description is scanty, and the only character of importance 
mentioned is, that the “ articular surface is very slightly con¬ 
cave, with a small round depression at the centre.” 
Of such vertebral bones there is in the Woodwardian Museum 
an associated series of 30, arranged over Cabinet lxxxiii. ; and 
there are 7 more unassociated in Case lxxxiv., and except a cer¬ 
vical among the latter all are dorsal. There is one character in 
these and all other dorsal vertebrse of Pliosaurus from Ely very 
peculiar, in that from the neural arch being placed so far forward 
the upper part of the anterior articular surface of the centrum 
projects and hangs over the corresponding part of the posterior 
surface of the adjacent vertebra, which retreats; hence the whole 
vertebra is oblique and leans forward. 
