CROCODTLIA. 33 



is the displaced tooth which is cemented by the matrix to the palatal surface of the 

 premaxillary in fig. 2. The enamelled crown shows the fine raised longitudinal ridges 

 better developed than one usually sees them in modern Crocodiles. There are twenty- 

 one alveoli on each side of the upper jaw. 



In all the particulars in which the skull under description differs from that of the 

 Crocodilus toliapicus, it departs further from the nilotic crocodile, and resembles more 

 the Gavial-like Crocodile of Borneo ; and as one of the old Egyptian names of the 

 Crocodile, Champsa, has been applied generically to the Gavials by some recent 

 Erpetologists, I have adopted the term ' Champso'ides' to signify the resemblance of 

 the present extinct species of Eocene Crocodile to the Gavials. 



The basioccipital condyle, together with the condyloid processes of the exoccipital, 

 project backwards in the Croc, champso'ides farther than in any modem Crocodile ; and 

 the supraoccipital 3, fig. 4, T. Ill, descends nearer to the foramen magnum. 



The upper jaw is more depressed, and the suborbital part of the maxillary bone 

 is much less inclined to the vertical in the present skull than in the original of Dr. 

 Buckland's figure of the Crocodilus Spenceri, which in other respects more nearly 

 resembles the Croc, champso'ides than the Croc, toliapicus ; the difference above specified 

 seems to be greater than can be accounted for by any accidental pressure to whi^h 

 the fossil skull figured in T. Ill can have been subjected. The mutilated skull to 

 which the term Croc. Spenceri was originally applied, is defective, as I have said, in the 

 facial or maxillary portion which is requisite for its unequivocal determination to 

 either of the two species which the more perfect specimens since acquired have 

 proved to have existed at the Eocene tertiary period. The form of the mutilated 

 portion of skull, and the figure of it given in PI. 25' of the ' Bridgewater Treatise,' might 

 well appear to indicate a short and broad snouted species of true Crocodile ; but if it 

 be not distinct from the two better represented species above described, I should be 

 more inclined to refer it to that which has the longest and narrowest snout, from the 

 conformity of the characters of the part of the skull which is preserved. A view of the 

 palatal surface of the specimen in question is given in T. II, fig. 2. 



Crocodilian vertebra referable to the two foregoing species of Sheppy Crocodiles. 



Not more than two species of Crocodile are indicated by the detached vertebrae 

 from Sheppy ; but the different proportions of the homologous cervical vertebrae, 

 fig. 3 and 7, T. V, and of the characteristic biconvex caudal vertebra, fig. 7, T. IV, and 

 fig. 10, T. V, would have determined the fact of there being two distinct species, 

 had their cranial characters, which are so satisfactorily demonstrated in T. II A and 

 T. Ill, remained unknown. I refer, provisionally, the shorter and thicker vertebrae to 

 the Crocodilus toliapicus with the shorter and thicker snout, and the longer and thinner 

 vertebrae to the Croc, champso'ides with the snout of similar proportions. 



5 



