332 Geological Society. 



the slender terminal caudal vertebrae of the Iguanodon are also hex- 

 agonal, and not cylindrical as in the Cetiosaurus. 



As there is no known extinct saurian which can so nearly com- 

 pete in size with the Cetiosaurus as the Iguanodon, it is fortunate, 

 Prof. Owen observes, that the distinguishing characters are so well 

 marked and easily recognizable. 



Dorsal vertebra. — The only portion of a dorsal vertebra described 

 in the memoir is the extremity of a spinous process, the posterior 

 surface of which is rough and flattened, 4 inches across, at about 

 the same distance below the end of the spine ; the sides are traversed 

 to a certain extent by a longitudinal ridge, anterior to which they 

 are concave and smooth, but their anterior margin is again flattened 

 and rough, though it is not so broad as the posterior. 



In referring all the vertebrae described in this paper to the same 

 species of saurian. Prof. Owen admits that they present a somewhat 

 greater variety of form and proportion in different regions of the 

 tail than is observable in that part of the vertebral column in the 

 smaller and recent species of Crocodile or Lizard ; not only beco- 

 ming larger in proportion to their thickness, but increasing slightly in 

 length for a short distance as they recede from the sacrum. They 

 appear likewise to exchange from a cylindrical to a subtriedral 

 form of the body, but to resume the cylindrical shape in the termi- 

 nal half of the tail. These modifications, he says, are possible, as 

 in the Plesiosaurus brachydeirtis still greater discrepancies in the 

 projiortions of the vertebrae prevail ; and they are inferior in degree 

 to any of the modifications which distinguish the vertebrae of known 

 genera of saurians from those under consideration, in pointing at 

 their distinguishing features from the hitherto known sauria ; and 

 in thus treating of them collectively, the inference that they belong 

 to the same gigantic species is, the author observes, almost irresist- 

 ible, that they belong to a new and distinct genus, which, on ac- 

 count of the vertebrae approximating in size and structure to the 

 vertebrae of the whale, he has termed Cetiosaurus. 



In the cuttings for the London and Birmingham Railway near 

 Blisworth, there were found, scattered over an area of 12 feet by 8 

 feet, the following remains : — 1. A bone resembling the episternal 

 of an Ichthyosaurus, the length or antero-posterior extent of the 

 preserved portion of the median plate being H foot, and the breadth 

 of the posterior fractured end 5 inches, from which it gradually ex- 

 pands to the root of the side branches, where its breadth is 1 foot. 

 From its obtuse termination to the end of the longest branch is '21 

 feet, and from this end to that of the opposite branch 4i feet. 

 2. The remains of a coracoid and scapula apparatus of equallj"^ gi- 

 gantic proportions. 3. A fragment, considered to be the shaft of 

 a humerus, 1 foot 9 inches in length, 6 inches in diameter across the 

 middle and 8 inches across the widest end. 4. A portion of the oppo- 

 site humerus. 5. Another fragment, believed to be part of a radius 

 or ulna, about a yard in length, G inches across the proximal end 

 and 5 inches across the middle of the shaft. G. A slightly curved 

 portion of a rib, a yard long and from 1 h to 2 inches thick. 7. Five 



