GEOLOGICAL SOCIETY OF LONDON. 



49 



in the carapace of the turtle. Eleven of the vertebral plates 

 are preserved^ only the two last being deficient, and eight 

 pairs of expanded ribs, the six anterior pairs exhibiting suffi- 

 cient portions of the narrow tooth-like extremities to deter- 

 mine the marine character of the fossil ; it is shown that the 

 last pair of ribs articulates with the ninth, tenth and ele- 

 venth vertebral plates, as in the Chelonice. The sternum 

 though more ossified than in existing marine turtles, yet 

 possesses all the essential characters of the genus. The evi- 

 dence thus afforded, proves that these fossil remains be- 

 longed to a true Chelone, but specifically distinct from any 

 now known to exist ; and he purposes to designate it, from 

 the shortness of the facial part of the skull as compared with 

 its breadth, Chelone hreviceps. 



The second species is indicated by a cranium possessing a 

 peculiarly prolonged pointed muzzle ; but these modifications 

 are proved by the author to demonstrate the marine nature 

 of the fossil as strongly as in the first species ; and the palatal 

 and nasal regions to afford further evidence of affinities to 

 turtles. It is distinguished from existing Chelone by the 

 narrowness of the spheroid at the base of the skull, and by 

 the form and grove of the pterygoid bones. This fossil 

 Mr. Owen names Chelone longiceps. 



The third species has been established from a considerable 

 portion of the bony cuirass of a young turtle three inches in 

 length, including the second and the seventh vertebral 

 plates, with the expanded parts of the first six pairs of ribs, 

 and the hyosternal and hyposternal elements of the carapace. 

 It differs from all known chelonites in the greater relative 

 breadths of the vertebral scutes, which are nearly twice as 

 broad as they are long ; he therefore proposes the name 

 Chelone latiscutata. 



The fourth species is indicated by a nearly complete cui- 

 rass, and is considered by the author to occupy a somewdiat 



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