4 FOSSIL REPTILIA OF THE LONDON CLAY. 



in connection with the intervening neural plates, which are entire save some abrasion of 

 the outer surface of the hinder ones and slight mutilation of the sutural borders. 



The costal plates, of which the proximal parts of four are preserved on the right side, 

 have been slightly dislocated from their marginal sutures with the neural plates by super- 

 incumbent pressure. A longitudinal extent of eight and a half inches is preserved of 

 the left sixth costal plate. 



On the under part of the mass of petrified clay to which the above-described 

 portion of carapace is cemented the expanded sternal portions of the pair of cora- 

 coid bones are preserved converging to the median line ; a portion of the xiphoid 

 production of the entosternum extends along the medial line in advance of the 

 broad ends of the converging coracoids. This is the chief recognisable part of the 

 plastron here preserved, but it adds to the testimony against the Sphargis affinity, in 

 which genus the entosternal does not send backward such xiphoid process. 



The breadth of the sternal end of the coracoid of Chelone gigas is six inches ; that 

 of the scapular end shown in another portion of the matrix is two inches and a half ; the 

 total length of the coracoid is one foot five inches. 



