WILLISTON: NEW CRETACEOUS TURTLE. g 



Cervical vertebrae. 



The specimen, as I received it, showed crowded into the posterior 

 temporal opining three cervical vertebrae. With much labor one of 

 these has been removed which presents important characters, all dis- 

 tinctly Pleurodiran. The anterior surface of the centrum is markedly 

 convex, but much broader from side to side than from above down- 

 ward, being subtriangular in shape. The posterior zygapophyses are 

 elongated and evidently arched downward. The arch above is gently 

 convex. Near the posterior part of the centrum on each side is a 

 very stout transverse process. The posterior articular surface of the 

 centrum has been injured, but is convex. The measurements of this 

 vertebra are as follows: 



Length of centrum from rim to rim 26 mm. 



Width of anterior articular surface 26 



Vertical diameter of the same 15 



Width through transverse processes 64 



Thickness of transverse processes 17 



Diameter of neural canal, transverse 13 



" " " " vertical 14 



Caudal vertebrae. 



Several caudal vertebrae are preserved, one of the largest of which 

 is shown in the plate VI, fig. 4. They are all small, and indicate a 

 small and short tail. The centrum is moderately elongated, with 

 well-developed zygapophyses, and rudimentary transverse processes. 

 The anterior end of the centrum is concave, the posterior convex. 

 Its measurements are as follows: 



Length of centrum 17 mm. 



Height of vertebra 22 



Vertical diameter of cup 12 



Pectoral girdle and extremity. 



The bones of the pectoral girdle and extremity preserved were 

 found so little distorted from their natural position that their mutual 

 relationships are assured. The scapula and coracoid Were found be- 

 tween the carapace and plastron near together. A part of the cora- 

 coid has been lost, but the inner end was lying in apposition to the 

 inner end of its mate. There is one nearly complete humerus pre- 

 served and close to the lower end of both were the bones of the fore- 

 arm and the metacarpal bones which are figured. Unfortunately, 

 the single bone figured as carpal or tarsal had been separated from 

 the matrix and its position is unknown. The four bones of the meta- 

 carpus were lying nearly in position, the two inner ones crossed over 

 each other. Lying across them and undoubtedly belonging with them 

 is the fifth bone. 



