CHELONIA. 69 



across the plastron between the posterior ends of the bony lateral walls, uniting the 

 carapace and plastron. 



Inches. Lines. 

 The breadth of the plastron is ..... 5 10 



The outer posterior extent of the lateral wall is ... 3 9 



The breadth of the entosternum ...... 1 5 



The depth of the whole bony cuirass at the middle line is . 4 



In the convexity of the carapace and relative depth of the osseous box, the Sheppy 

 Chelonite slightly surpasses most existing species, resembling in this respect the Emi/s 

 ncdlata and Cistudo Carolina. The plastron is also slightly concave, as in the male of 

 CistuJo vulgaris: it is, however, entire at the line where the transverse joint of the 

 plastron exists in the box-tortoises ; and the extent and firm ossification of the lateral 

 supporting walls of the carapace forbid likewise a reference of the fossil to those genera. 



The general characters of the present fossil, more especially the uniformity of 

 size and breadth of the preserved vertebral plates and ribs, prove it to be essentially 

 related to the fresh-water or Emydian Tortoises. It exceeded in size, however, almost 

 all known Emydians, and was almost double the dimensions of the Emydian species 

 {Cistudo Eurojjea) now inhabiting central Europe. It appears, like the Cistiidities, to 

 have approached the form of the land tortoises, in the convexity of the carapace, but 

 without possessing that division and hinge of the plastron which peculiarly distinguishes 

 the box-tortoises. The contraction of the anterior aperture of the bony cuirass 

 especially transversely as compared with the Platemydians, would indicate more 

 restricted powers of swimming, and consequently more terrestrial habits. In the 

 thickness and strength of the bones of the buckler, especially of the sternum, we may 

 discern an approach to the genus Testudo. 



Assuming that the Chelonite here described may be identical with that of which 

 the carapace from Mr. Crow's collection is figured in the ' Ossemens Fossiles,'* the 

 " Emi/s de Sheppi/" of Cuvier will be one of the " synonyms" of the present species. 

 Mr. Gray, in his ' Synopsis Reptihum,' 8vo, 1831, has given Latin names to all the 

 fossil reptiles indicated or estabhshed by Cuvier, and has called the "Emi/s de Slieppi/' 

 " Emys Parkinsonii" referring as representations of this species, not to the figure of the 

 carapace above cited, which may belong to the same species as the present Emp, but 

 to the figure of the plastron, copied by Cuvier from Parkinson's ' Organic Remains,' 

 and to the figure of the skull in the same work, both of which most unquestionably 

 belong to the genus Chelone and not to the genus Emys. 



The " Emys Parkinsonii " of Mr. Gray is a synonym of my Chelone lonpceps. 

 Cuvier's name, — which, besides the claim of priority, is the result of laborious and 

 direct comparison devoted to the elucidation of its subject, — if rendered into Latin 

 would be Emys toliapicus ; but as the species to which it refers may not be the one 



* Ed. 1824, vol. V, part ii, pi. 1 j, fig. 12. 



