68 REPORT— 1841. 



of a distinct species, under the name of Crocodilus cultnde7is* . The crown 

 is laterally compressed, subincurved, with two opposite trenchant edges, one 

 forming the concave, the other the convex outline of the tooth. In the 

 Gavial, the direction of the flattening of the crown and the situation of the 

 trenchant edges are the reverse, the compression being from before back- 

 wards, and the edges being lateralf . The tooth of the Crocodilus cultridens 

 thus resembles in form that of the Megalosaur, and perhaps still more those 

 of the Argenton Crocodile ; but I have not observed any specimens of the 

 Wealden teeth in which the edges of the crown "were serrated, as in both the 

 reptiles just cited. The teeth of the Crocodilus cultridens also present a 

 character which does not exist in the teeth of the Megalosaur, and is not at- 

 tributed by Cuvier:(: to those of the Crocodile d'Argentofi. The sides of 

 the ci-own are traversed by a few longitudinal parallel ridges, with regular 

 intervals of about one line in breadth, 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 sooner at the convex than at the concave side of the crown. 



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

 skeleton of the present extinct Crocodilian; but from the well-marked dif- 

 ferences between these teeth and those of all other known species, it is most 

 probable that the extinct Crocodile formed the type of a distinct sub-genus, 

 for which the term Suchosaurus might be applied. 



In the Wealden strata, biconcave Crocodilian vertebrae have been dis- 

 covered by Dr. Mantell differing in form from those of the Crocodilian with 

 obtuse teeth, and readily distinguishable by their compressed and wedge- 

 shaped body from those of all other known Crocodilians. It is highly pro- 

 bable that these remarkable vertebrjE are parts of the same animal as the 

 above described and equally remarkable compressed teeth. 



No. 2133, Mantellian Collection, is the body of a dorsal vertebra of this 

 species of Crocodilian, with both articular extremities slightly and equally 

 concave : though rather narrower at the middle than at the ends, it is more 

 uniformly compressed than in other Crocodilian vertebraj, the sides con- 

 verging to an inferior obtuse ridge, which is very slightly concave in the 

 antero-posterior direction. The sides are not flat in the vertical direction 

 nor slightly concave, as in many of the Iguanodoiis vertebras, to which the 

 present form approximates ; but are gently convex, so that a pencil laid ver- 

 tically upon the side touches it only by its middle. A more decided differ- 

 ence between the present crocodilian vertebras and those of the Iguanodon 

 is, that the former are longer in proportion to their height and depth. The 

 external surface at the middle of the body of the vertebra is very finely stri- 

 ated, so as to present a silky appearance ; near the margins it is sculptured 

 by coarse longitudinal grooves and ridges. 



The base of the neurapophysis, which, when anchylosed, leaves an evident 

 trace of the suture, is nearly equal in length with the body of the vertebra ; 

 it does not wholly include the spinal canal, but leaves the impression of the 

 lower third of that canal upon the upper surface of the centrum. 



* Tl\ese teeth are referred by M. II. v. Meyer to the genus Teleosaimis ; but no portions 

 of the skeleton of a Telcosaur have hitherto been found in the Wealden. Tlie figures of 

 the teeth of Suchosam-us cultridens, published ))y Dr. Mantell in the ' Illustrations of the 

 Geology of Sussex,' pi. v. lig. 5, 6, 8, ai-e those cited in the ' Palseologica,' p. 115. The other 

 teeth attributed to the same species of Teleosaurus, hy II. v. Meyer, out of Mantell, I. c. 

 pi. V. figs. 1, 2, 7, 9, 10, 11, appertain to a genus equally distinct from Suchosaurus and from 

 Teleosaurus. 



t The tootli attributed by M. Deslongchamps to the PoiMlopleuron, agrees in form w^th 

 those of the Gavial, and differs in the characters cited in the text from those of the Croco- 

 dilus cultridens. % Cu\'icr, i.\. p. 331. 



