74 FOSSIL REPTILIA OF THE LONDON CLAY. 



long, but the lateral angle is near the anterior margin, as in the preceding plates. 

 The ninth (.^g) is somewhat expanded posteriorly, but less so than usual. 



The sixth and seventh of the neural plates are considerably raised towards the 

 centre, but with a slight longitudinal depression along the median line ; and there is 

 a considerable triangular or wedge-shaped elevation, commencing with its base near 

 the anterior margin of the eighth, and extending to the posterior margin of the ninth 

 neural plate. 



The costal plates {j)h — 8) diflFer from those of the species in general in being more 

 regularly parallel at their lateral margins. 



The first vertebral scute reaches to the posterior third of the first neural plate (yi), 

 and its lateral margins are expanded forwards, but with a slight curve. The second 

 and third {v2, 3) have nearly parallel sides, and are both longer than they are broad, 

 the lateral angles being extremely inconsiderable ; the fourth (^4) is hexagonal, but 

 still with short lateral angles ; the fifth (w5) has the lateral margins, and, as usual, 

 becomes broader posteriorly. 



As the costal or lateral scutes depend, in the only important and variable part of 

 their contour, on the form of the margins of the vertebral, it is unnecessary to 

 describe them. 



The plastron "(T. XXVI) occupies about its usual relative proportion to the 

 carapace, but it has been so much broken as to afford but little opportunity for any 

 satisfactory or useful description. It would appear, however, from the extent of the 

 openings for the passage of the limbs, that the animal must have possessed considerable 

 powers of swimming, offering in this respect a very marked contrast to the testudiniform 

 character of E. Comjdoni and E. testudiniformis. 



Foot. Indies. Lines. 



Probable total length of the carapace .... 1 



Probable total breadth of ditto .• ... 1 



Depth of the bouy case ...... 3 3 



T. B. 



Emys Delabechii. Bell. Tab. XXVIII. 



An almost gigantic specimen of the fluviatile form of scutate Chelonia, in the 

 collection of the Geological Survey, forms the subject of the present description. It 

 is from the London clay of the Island of Sheppy. 



This species far surpasses in size any known Emydian, whether fossil or recent ; 

 the carapace having been certainly not less than one foot nine inches in length and one 

 foot five inches in breadth. It very clearly belongs to the form to which I have 

 assigned it, and in some of its broader characters approximates considerably to the 

 last species, E. bicarinata. The specimen is, however, unfortunately so badly injured, 

 partly by having been originally much crushed, and partly by recent disintegration. 



