14 FOSSIL REPTILIA OF THE 



attributed by Cuvier l to those of the Crocodile d'Argcnton. The sides of the crown are 

 traversed by a few longitudinal, parallel ridges, with regular intervals of about one line, 

 in a crown of a tooth one inch and a half in length ; these ridges subside before they 

 reach the apex of the tooth, and more rapidly at the convex than at the concave side of 

 the crown. 



Hitherto these teeth have not been found so associated with any part of the skeleton 

 of the same species as to yield unequivocally further characters of the present extinct 

 Crocodilian. From the above-mentioned well-marked differences between these teeth 

 and those of all other known species, I regarded the extinct Crocodile in my ' Report on 

 British Fossil Reptiles ' as forming the type of a distinct genus and species, and proposed 

 for it the term Suchosaurus cultridens. It indicates a nearer affinity or transition to the 

 Dinosaurian order than does any of the mesozoic Crocodilia, known by their cranial as 

 well as by their dental, vertebral, and dermal characters. 



Of those species so recognised, including the Purbeck and Wealden kinds now 

 added, the following are common characters. A greater development, than in Tertiary 

 Crocodiles, of the dermal bony armour, which consists, without exception, of both 

 dorsal and ventral scutes, the scutes in each series well connected with each other, and 

 in Goniopholis exceptionally so. 



A less development of the osseous surface for the origin of the muscles of the mandible 

 indicated at the upper surface of the cranium by the larger ' temporal vacuities,' and at 

 the under surface by the smaller pterygoid plates. Horizontal plane, larger size, advanced 

 position and palato-pterygoid formation of the palatonares. 



Amphiccelian vertebras. 



These common characters of mesozoic Crocodilia suggest considerations of their 

 relation to the prey of such Crocodilia and also to the coexistent marine reptiles of which 

 those Crocodilia themselves became the prey. 



Similarly, if the common characters of the tertiary and existing Crocodilia be 

 summed up they become suggestive of analogous considerations. 



A minor development than in mesozoic crocodiles of the dermal bony armour, 

 consisting, with few exceptions, of the dorsal scutes only, and these relatively smaller, 

 thinner, and less closely knitted together, may relate to the absence of the Mosasaurs, 

 Pliosaurs, Polyptychodonts, &c, against the assaults of which the contemporary 

 crocodiles of those Saurians required a better defensive armour. 



The greater development of the osseous surface for the origin of the muscles of the 

 mandible, indicated at the upper surface of the cranium by the smaller, or obliterated, 

 'temporal vacuities,' and, at the under surface, by the more expanded alas of the 

 pterygoids, accords with the stronger jaws and dentition, as an adaptative to seize and 

 subdue a stronger and more resisting kind of prey than that on which the mesozoic 

 crocodiles habitually fed. 



1 Cuvier, 'Ossem. Fossiles,' 8vo. torn, ix, p. 331. 



