OPHLDIA. 63 



inferior spine, the remaining vertebra to the tail being merely ridged beneath : but I 

 have not met with such modifications in the trunk-vertebrae of the same existing 

 Serpent, as those that have been pointed out in the vertebrae (figs. 5, 6, and figs. 14, 

 15) ; and in no specimen of Python or Boa, have I found the vertebrae presenting such 

 differences of character as those indicated in the larger fossil Palseophidian vertebras 

 which I have described as ' ridged' and ' not ridged.' Leaving therefore the question 

 of the nature of the differences in the smaller vertebras (figs. 1 and 14) open, and as 

 possibly depending upon difference of age and position in the series, 1 believe the 

 characters of the ridged vertebra to be those of a distinct species of Palceophis. 



Masses of mutilated vertebrae and ribs, irregularly cemented together by their 

 matrix, are occasionally though rarely discovered in the Eocene clay at Bracklesham. 

 The specimens of such aggregates which I have as yet seen have not exhibited any 

 vertebras sufficiently complete to yield more than the means of determining the generic 

 relations. That of which a small portion is figured in T. XVI, fig. 4, is the most 

 instructive, since it shows the form and structure of the ribs. The proximal half of 

 the pleurapophysis (pi) equals in size the corresponding part in the Python regius of 

 twenty feet ; it shows the same fine cancellous structure of the articular end, and a 

 similar medullary cavity, with thin compact walls, forming the body of the vertebra. 

 The more slender distal portion of another rib is preserved, with the medullary cavity 

 exposed at its fractured parts. 



Pal^ophis toliapicus, Owen. Tab. XV and XVI. 



Transactions of the Geological Society of London, vol. vi, part ii, p. 209. 



Report on British Fossil Reptiles, in the Report of the British Association, 1841, p. 180. 



The fossil Ophidian vertebrae which have been discovered in the London clay at 

 Sheppy are, for the most part, smaller than those from Bracklesham ; their common 

 dimensions equalling those of a Boa constrictor of from ten to twelve feet in length. 

 They all repeat, however, the generic modifications characteristic of Palaophis; the 

 hinder margin of the neurapophyses (T. XV, fig. 5) is produced into a pointed or 

 angular plate ; the articular prominence for the rib (ib., fig. 3, d) is wholly convex ; the 

 zy gapophyses are short, and no diapophysial point extends beyond the anterior ones ; the 

 height of the neural spine (T. XV, fig. 1, and T. XVI, fig. 2, ns) exceeds its antero-posterior 

 extent. The veritable Ophidian character of the Reptile to which these fossil vertebrae 

 belonged, is not only shown by their individual structure, but is well illustrated by the 

 number of them in natural articulation which have occasionally been found cemented 

 together in the petrified clay. 



One of these Ophidiolites from the clay of Sheppy, in Mr. Bowerbank's collection, 

 exhibits a portion of the vertebral column of the Palceophis suddenly bent upon itself, 

 and indicating the usual lateral flexibility of the spine : in another specimen, including 

 about thirty vertebrae, the vertebrae have been partially dislocated and are bent in a 

 semicircle, Tab. XVI. 



