340 



TEE PORTLAND OOLITE PERIOD. 



CHAP. 



It may be useful, however, to give it a name for reference, in hope 

 that some day the jaw may be found in apposition with the vertebral 



Diagram CXXXII. Tooth of Ichthyosaurus or Polyptychodon. 



column. The striated part or crown terminates toward the base 

 in a regular curve across the conical surface, the several striae 

 coming there to a sudden truncation. 



The diagrams which follow represent some bones of Ichthyosaurus, 

 which cannot at present be referred to species, though it is probable 

 they belong to Ichthyosaurus trigonus. 



2 34 



Diagram CXXXIII. i. Coracoids. 2. Scapula. 3, 4. Humerus. 



