56 FOSSIL REPTILIA OF THE LONDON CLAY. 



smaller than in the Naja; the neural spine (ns, fig. 17) is lower in proportion to its 

 antero-posterior extent. The pleurapophysis (pi) is shown articulated to the tubercle 

 in figs. 19 and 20. 



The vertebrae of the common harmless Snake, Coluber natricc, differ only in size 

 from those of the larger continental species above described. 



In an African Eryx (T. XIII, figs. 21-24) the diapophysis (d) does not extend beyond 

 the articular surface of the anterior zygapophysis (z), but is exclusively devoted to 

 forming a low, subconvex, articular tubercle, which has a longitudinal depression an- 

 teriorly; the posterior margin of the neurapophysis (fig. 21,^) forms an angle above the 

 zygantrum, which angle, though slight, is more marked than in any of the foregoing 

 Ophidians ; the hinder end of the hypapophysial ridge (h) is slightly produced ; the 

 zygapophyses (z, z, fig. 24) are less extended outwards than in the Pythons. 



In a Sea-snake (Hydrophis bicolor, T. XIII, figs. 25-28) I find the height of the neural 

 spine (fig. 25, ns) greater in proportion to its antero-posterior extent than in any of the 

 foregoing Ophidians. The diapophysis (d) sends a point (d") outwards a little beyond 

 the articular surface of the anterior zygapophysis (z) ; a very small hypapophysis (h) 

 projects below the articular ball of the centrum, and a low ridge is continued forwards 

 from it (fig. 28) ; the posterior border of the neurapophysis (fig. 25, n) forms no angle, 

 but is moderately convex, as in all the foregoing Ophidians, excepting the Eryx. 



With this indication of the kind and extent of the vertebral characters of the 

 different species of Serpent which I have been able to study in reference to the fossils 

 to be described, I proceed to the comparisons by which the following extinct genera 

 and species have been established. 



Genus — Pa ~lje o p h i s . 



Paljeophis Typhous, Owen. Tab. XIII, figs. 5-8, Tab. XIV, figs. 1-3, 7-9, 16, 17, 

 26,27,28. (Fig. 6, 10-12)? 



Amongst the numerous vertebrae of this species of Serpent which have come under 

 my examination, a few, of small size, have shown the hypapophysis long and com- 

 pressed, as in the specimen in Mr. Bowerbank's collection, figured in T. XIV, figs. 1-3, h, 

 indicating that the vertebrae at the anterior part of the trunk had that character, as in 

 the large existing Serpents ; whilst all the larger vertebras, with the hypapophysis 

 perfect, manifest shorter proportions of that process, as in the typical example, 

 apparently from the middle of the abdomen (T. XIII, figs. 5-8, h) ; whence I infer that 

 the Palaophis resembled the Python, Boa, Coluber, and Hydrus, in having different 

 proportions of the hypapophysis at different parts of the vertebral column. Had 

 every fossil vertebra shown a long hypapophysis like that in T. XIV, fig. 1, we might have 

 suspected that the species had been of the venomous family, like the Rattlesnake. 



The veritable Ophidian nature of the fossils in question is demonstrated, not only 



