A FOSSIL CHELONIAN REPTILE, FROM THE MIDDLE PURBECKS. 69 



been incorporated in the whole structure of the shell. The eight 

 broad flattened ribs, which retain their breadth throughout, 

 from their proximal to their distal ends, are united by longitu- 

 dinal sutures, and independent of the marginal plates; this 

 sutured union is well shewn in the specimen. The exterior sur- 

 face of the carapace is granulated, and on approaching the bor- 

 der the granulations are substituted by a series of very fine 

 lines at right angles to the border, and are marked strongly 

 where the marginal plates overlap. There are no concentric 

 impressions indicative of growth of the scutes. 



This specimen is from the Middle Purbecks, of Swan age, and 

 at present is in my possession. 



