chelonid^:. 69 



30255 a. A very similar specimen. Purchased, 1857. 



35189, 35190, 35192. Three imperfect specimens of the symphysis 

 of mandibles belonging either to the present or preceding 

 form. Purchased, 1859. 



41797. The imperfect symphysis of a mandible of the same general 

 type. Purchased, 1864. 



The following type of humerus is provisionally referred to the present 

 species. These bones agree in relative size with the mandibles, 

 and the first of them may have been associated with the type 

 mandible. They are in any case referable to the Chelonidse, 

 and differ from those of the type genus. 



35175. The right humerus. Figured by the writer in the 4 Quart. 

 {Fig.) Journ. Geol. Soc' vol. xlv. p. 235, fig. 3. The middle of 



the shaft is wanting, and is restored in plaster, so that the 

 contour of this is only approximate. "With the exception 

 of the solid radial process, and the greater constriction of 

 the shaft, this specimen accords generally with the humerus 

 of Tlialassochelys. It also presents a striking resemblance 

 to the two humeri figured by Leidy in his ' Cretaceous 

 Eeptilia of the United States ' (Smiths. Contrib. Knowl. 

 1864), pi. viii. figs. 1-4, as those of Mosasaurus : and 

 subsequently referred by Cope (see Rep. TJ. S. Greol. Surv. 

 Terrs, vol. ii. p. 113, 1874) to the Athecata, under the names 

 of Protostega tuberosa and P. neptunia. Those specimens 

 differ markedly from the typical humerus of that genus, 

 and appear to belong to the Chelonidce. Purchased, 1859. 



35176. The imperfect proximal extremity of a slightly larger left 



humerus. Purchased, 1859. 



35194. The imperfect proximal extremity of a considerably larger 

 right humerus. Purchased, 1859. 



35199. The imperfect proximal extremity of a left humerus of con- 

 siderably smaller size than No. 35175. Purchased, 1859. 



35207. The distal extremity of a left humerus agreeing in size with 

 No. 35176. Purchased, 1859. 



35207 a. The distal extremity of a smaller left humerus. 



Purchased, 1859. 



