Geological Society. 333 



caudal vertebrze agreeing in dimensioiis with the vertebrae of Chiji- 

 ping Norton. 



Numerous fragments of long bones without a trace of a medullary 

 cavity have been found at Chijij^ing Norton, and correspond in mag- 

 nitude with the vertebrae. The articular surfaces which are pre- 

 sers'ed are covered with large tubercles for the attachment of thick 

 cartilages. The best preserved fragments are considered to belong 

 to metacarpal or metatarsal and phalangeal bones, and are therefore. 

 Prof. Owen says, decisive evidence against the cetacean nature of 

 the animal ; but he adds, they possess characters by which they 

 may be distinguished from the corresponding bones of known ex- 

 tinct gigantic saurians. One of these bones, believed to be a meta- 

 carpal or a metatarsal, is double the bulk of the largest analogous 

 bone of a full-grown elephant, though the metacarpals or metatar- 

 sals are much smaller in proportion in Saurians than in Pachyderms. 

 The bone is 7 inches in length, 9 in circumference in its middle, 5 

 in the antero-posterior diameter of its proximal end, and 4 inches 

 8 lines in the transverse diameter of the distal end. A proximal 

 phalanx is shown to be remarkable for its short and broad propor- 

 tions, which are more massive than those of the phalanges of exists 

 ing Crocodilians or of the Poikilopleuron. 



An ungueal phalanx, also found at Chipping Norton, was 6 inches 

 in length, 1\ in breadth, and upwards of 3 in depth. It was slightly 

 curved, obliquely compressed, obtusely terminated with a shallow, 

 concave, trochlear articular surface, divided by a vertical convexity ; 

 it was marked on each side by a smooth curved groove, 3 inches 

 in length, with the concavity downwards, and the lower edge pro- 

 jecting beyond the upper at the posterior part of the groove ; but it 

 is shown to be by no means produced in so large and thick a ridge 

 as that which characterizes each side of the more depressed and 

 broader phalanx of the Iguanodon. From the ungueal phalanges of 

 that Saurian it differs in being much less compressed from side to 

 side and less curved downwards. It vastly surpasses in size any 

 of the ungueal phalanges of the Poikilopleuron. A smaller ungueal 

 phalanx, resembling in general shape the above, was found at Chip- 

 ping Norton ; and portions of metacarpal or metatarsal bones, agree- 

 ing in form and size with the fragments obtained at Chipping Nor- 

 ton, have been discovered at Buckingham : also a fragment 8 inches 

 long, which Prof. Owen considers to have belonged to a radius, a 

 fibula, or a long distal phalanx. 



With reference to a comparison of the remains of the Cetiosaurus 

 with those of the Polyptychodon, the bones of the extremities pre- 

 sent in both cases the cancellous structure throughout the central 

 part, which indicates aquatic rather than terrestrial habits. Prof. 

 Owen states that he has not found any of the remains of the extre- 

 mities of the Cetiosaurus to agree exactly in sliape with those be- 

 longing to the Polyptychodon ; also that no specimen of a tooth 

 agreeing in characters with the teeth of the Polyptychodon has been 

 detected in secondary strata inferior to the grcensand. Certain 

 large conical teeth, found in the Malton oolite, may, Mr. Owen 



