XI. 



CETEOSA UR US ULN&. 



275 



Ulna. -A pair of remarkable bones, somewhat pyramidal in shape, 

 with an approach to a three-sided section, was obtained by the 

 workmen at a time when we were not present. 



Regarding them as ulnae, the shaft is in som^ degree trihedral 

 especially toward the proximal end, where the sides may be taken 



Diagram GUI. Ulna of Ceteosaurus. Scale one-tenth of nature. 



i. Shewing the faces, & and c, and the truncation at d . 2. Bone of the opposite 

 side, shewing the same faces less crushed at the truncation. 3. Shewing the face, 

 a, of the same bone as fig. i. 2*. The cross section of the bone fig. a. 3*. The 

 cross section of the bone fig. 3. 



as a 12, b ii, and c 7 inches. The broadest side is there deeply 

 and widely hollowed (fig. 3); it meets the other broad face in a 

 rather thin expansion, and forms with the narrowest side a solid 

 mass, which, however, is (in both specimens) truncated at the angle 

 marked (d) in fig. T. and fig. 3. This truncation, where the narrow 



T 2 



