SUPPLEMENT 



TO THE 



EOCENE CHELONIA. 



Emys Conybearit, Owen. T. XIII and XIV. 



The subject of the present description is the most complete specimen of fossil 

 fresh-water Tortoise {Emys) which has hitherto come under my observation. It 

 was obtained, like the Emys Delabechii, Bell, which it most resembles, from the Eocene 

 clay of Sheppey Island, and forms part of the large and instructive collection of 

 Sheppey fossils belonging to J. S. Bowerbank, Esq., F.R.S. It consists of both 

 carapace (T. XXVIII A), and plastron (T. XXVIII B), giving the natural curves, depth, 

 and periphery of the portable abode of the animal. Every constituent bone of the com- 

 plex roof of this abode is preserved, and the impressions of every horny scute can be 

 traced, uninterruptedly, upon its uninjured surface. The floor or "plastron" is, unfortu- 

 nately, not so entire, but its margins are unbroken, exhibiting the characteristic 

 contour. 



The dimensions of this noble specimen of Eocene Emys fall little short of those of 

 the Emys Delabechii, the length of the carapace being 1 foot 65 inches, and its breadth 

 1 foot 3 inches. 



The forms and proportions of the nuchal {eh), pygal {py), and their connecting series 

 of median neural plates (« 1 to s 9), are accurately shown in T. XXVIII A : the eighth 

 neural plate is obliterated, or has its place taken by the extension of ossification of the 

 seventh and eighth costal plates towards the median line. The abraded and fractured 

 state of the carapace of Emys Delabechii* does not permit of a comparison of this 

 particular. 



There is no trace of a median elevation or keel in Emys Conybearit .- the neural 

 plates in Emys bicarinala-f are broader in proportion to their length than in the present 

 species, and the series is not interrupted. 



* ' Monograph on Fossil Reptilia of the Loudon Clay,' T. xxviii, Falseoritographical Memoirs for 1848. 

 t lb., T. xxv. 



11 



