64 FOSSIL REPTILIA OF THE LONDON CLAY. 



As compared with either of the species of Palceopkis from Bracklesham, the 

 vertebrae from Sheppy have the centrum proportionally longer and more slender, with 

 a smaller terminal cup and ball. In vertebrae from Sheppy and Bracklesham in which 

 those articulations were of equal size, the length of the neural arch at and including 

 the zygapophyses, was two centimetres in the Palceophis toliapicus, and one centimetre, 

 seven millimetres in the Palceophis Typhceus. 



The hypapophysial ridge is more constant and better marked ; it is produced at 

 both extremities, and most so at the hinder one, but here in a less degree than in the 

 Palceopkis Typhceus, or Pal. porcatus, and the ridge is not interrupted between the two 

 hypapophyses, as in most of the large vertebras of the Palceophis porcatus. On the 

 other hand, the rising of the bone continued from the anterior to the posterior 

 zygapophysis does subside midway more completely than in the Palceopkis Typhceus; and 

 the ridge, which in that species extends to the apex of the produced posterior border of 

 the neurapophysis along the outside of that aliform production, is less developed in 

 the Palceophis toliapicus : the neural arch is less suddenly compressed above, or 

 inclines more gradually to the base of the spine ; this spine, also, although its base is 

 extended to near the anterior border of the zygosphene, appears to be higher in 

 proportion to its antero-posterior extent than in the Palceophis Typhceus. The diapo- 

 physis is less produced outwards and downwards than in the Palceophis Typhceus or 

 Palceophis porcatus. In a group of thirty vertebrae of this species cemented together 

 by the indurated clay from Sheppy, in the Hunterian Collection, and which, in the 

 original MS. Catalogue of that part of John Hunter's Collection, were called 

 'vertebrae of a Crocodile,' T. XV, fig. 1, several of the long and slender subcylindrical 

 ribs are also preserved, in the fractured parts of which the medullary cavity is shown. 

 The articular surface at the proximal end presents the uniform concavity suited to the 

 convexity of the diapophysis. I have seen no evidence of the process from the upper 

 and back part of the proximal end of the rib which is present in the Python. 



The finest and most strikingly Ophidian example of the great fossil snake of 

 Sheppy has been obtained from that locality by Mr. Bowerbank since the publication 

 of the Memoir in which his earlier specimens of the Palceophis toliapicus were deter- 

 mined and described. It consists of a series of thirty vertebrae, from about the 

 middle of the abdomen, bent into an oval form upon their dorsal aspect, and measuring 

 twenty inches in length (T. XVI, figs. 1, 2). 



As the strong and complex articulations of these vertebrae in Serpents opposes 

 any inflection of the column except from side to side, their unnatural bend in the fossil 

 is attended with just the amount of mutual dislocation that was requisite to admit of 

 it ; but beyond this amount of dislocation, which chiefly affects the terminal ball and 

 socket-joints, the vertebrae have been preserved in their natural juxtaposition and 

 succession. The dead body of this eocene serpent has apparently sunk or 

 been washed into the great stream or estuary, where it has been driven about to 



