CRETACEOUS FORMATIONS. 23 



Both specimens are from the same quarry or pit at Burham, in Kent, were found at 

 the same time, and there is good reason to suppose in the same block of chalk. It 

 appears, however, that they were disposed of by the quarrymen to different persons, 

 and ultimately found their way to the two collections of which they are now respec- 

 tively the ornaments. 



Assuming, then, the two groups of vertebrae to have belonged to the same skeleton, 

 and the conformity in shape and size of the vertebrae and ribs favours the conclusion 

 which Mr. Dixon had drawn from the historical evidence, we may then enumerate fifty- 

 seven vertebrae between the skull and the pelvis, supposing that none have been lost 

 between the end of the specimen in T. X, fig. 1, and the beginning of that in T. X, 

 fig. 4. Amongst existing Lizards this number of abdominal (cervical and dorsal) 

 vertebrae is equalled only by those snake-like species (Pseudopus, Pipes, Ophisaurus) 

 which seem to make the transition from the Lacertian to the Ophidian reptiles : but 

 not any of such genera manifest so well-developed a humerus and scapular arch as are 

 indicated in T. X, fig. 1, at 51 and 53, or so complete a sacrum and pelvic bones as 

 are shown in fig. 4, at 62 and 63. Of those existing Lacertians which had the hinder 

 extremities as well developed as in the extinct species under consideration, the greatest 

 recorded number of vertebrae between the skull and the sacrum is forty-one.* 



Although the evidence relating to the discovery of the specimens (fig. 4 and fig. 1, 

 T. X) is such as to lead me to deem it highly probable that they form the anterior 

 and posterior moieties of the backbone of the same individual ; yet, as it does not 

 amount to absolute demonstration, the characters of the Saurian in question must 

 for the present be rigorously deduced from those parts which are unaffected by such 

 uncertainty. In this'fit condition for scientific comparison must be regarded the frag- 

 ment of skull, and the chain of thirty-six vertebrae imbedded in one block of chalk, 

 and represented in T. X, fig. 1 . The most cautious and sceptical Palaeontologist must 

 admit, after scrupulous examination of the specimen, that the jaws and the portion of 

 vertebral column, which are accurately figured in the plate, have belonged to one and 

 the same animal, having been subject to no greater amount of dislocation than is 

 represented at the twenty-fifth vertebra for example, and in the position of some of 

 the ribs. Viewing the slight extent of displacement of any of these parts in the fossil, 

 it is very improbable that the scapular arch (51) should have been subjected to any 

 considerably greater degree of displacement ; and taking, also, into consideration the 

 gradual diminution of the vertebrae, as they extend forwards from the place of the 

 scapular arch in the fossil, at the eighteenth or twentieth vertebrae, to the cranium, 

 and the remarkable and striking difference in the shape and size of. the pleurapophyses 

 (vertebral ribs,^., pi.) in those anterior vertebrae, I am led to conclude that the position 

 of the remains of the scapular arch (51) in the fossil was, in relation to the vertebral 



* According to the table in Cuvier, Lecons d'Anat. Comp. i (1836), p. 221, e. g. in the Scincus oeellatus. 



