WILLISTON AND CASE: KANSAS MOSASAURS. 21 



MEASUREMENTS OF THE DORSAL VERTEBRAE. 



I. Length of centrum to rim of ball 38 millim. 



Transverse diameter of ball 20 



Vertical diameter of ball 19 



Height of spine above floor of neural canal 48 



Extent of articular surface of transverse process 30 



Width of spine 28 



4. Length of centrum to rim of ball. . 41 



Transverse diameter of ball 20 



Vertical diameter of ball 20 



Height of spine above floor of neural canal 48 



II. Length of centrum to rim of ball 4.1 



Vertical diameter of ball 22 



Extent of articular surface of transverse process 16 



Width of spine 32 



15. Length of centrum to rim of ball 41 



Transverse diameter of ball 21 



Vertical diameter of ball 24 



20. Length of centrum to rim of ball 42 



Vertical diameter of ball 25 



Height of spine above floor of neural canal 58 



24. Length to rim of ball 41 



Transverse diameter of ball 22 



Vertical diameter of ball 23 



Height of spine 4g 



28. Length to rim of ball 40 



Vertical diameter of ball 24 



Transverse diameter of ball . . . , 23 



Height of spine 54 



32. Length to rim of ball 38 



Vertical diameter of ball 25 



Transverse diameter of ball 24 



35. Length to rim of ball 37 



Caudal vertebrae. 



Immediately following the thirty-fifth rib-bearing vertebra there is 

 an abrupt change, the tubercular process for the rib giving place to an 

 elongated transverse process. From the position of the pelvis, it is 

 evident that the ilia were attached to the first pair of these. Precisely 

 this relation of pelvis to the vertebrae is found in such lizards as the 

 Monitor and Iguana, and it is probable that such is the relation in all 

 the Pythonomorpha. It will thus be seen that there are no distinct- 

 ively lumbar vertebrae, if by such are meant free, non-costiferous, 



