70 REPORT — 1841. 



numerous, more close-set, and more neatly defined than in the Suchosaums 

 cultridens. Two of the ridges, larger and sharper than the rest, traverse 

 o])posite sides of the tooth, from the base to the apex of the crown; they 

 are placed, as in the Crocodile and Gavial, at the sides of the crown, mid- 

 way between the convex and concave lines of the curvature of the tooth. 

 These ridges are confined to the enamel ; the cement-covered cylindrical 

 base of the tooth is smooth. The size.of the teeth varies from a length of 

 crown of two inches, with a basal diameter of one inch and a half to teeth of 

 one-third of these dimensions. 



Hitherto no teeth of the Goniopholis appear to have been discovered 

 in the oolite near Caen ; the only specimens resembling them being those 

 which Cuvier has stated to indicate a second species of Crocodilian, from the 

 Jura limestone at Soleure*. No other remains referable to this species are 

 noticed by Cuvier ; but the discovery of a portion of the skeleton, having in 

 the lower jaw two teeth identical with the obtuse teeth of the Wealden, has 

 thi'own much light upon the characters of this interesting species. 



The circumstances connected with this discovery are thus narrated by Dr. 

 Mantell : — " In the summer of 1 837, the workmen employed in a quarry in 

 the immediate vicinity of Swanage, had occasion to split asunder a large slab 

 of the Purbeck limestone, when, to' their great astonishment, they perceived 

 many bones and teeth on the surfaces they had just exposed. As this was 

 no ordinary occurrence, — for although scales of fishes, shells, &'c. were fre- 

 quently observed in the stone, bones had' never before been noticed, — both 

 slabs were carefully preserved by the proprietor of the quarry." They were 

 obtained by Robert Trotter, Esq., F.G.S., and presented by him to Dr. 

 Mantell, by whom the bones were relieved from the matrix, so far as their 

 brittle state would permit. The specimen has subsequently been purchased 

 by parliament, and, with the rest of Dr. Mantell's collection, is now depo- 

 sited in the British Museum. 



Figures of this interesting group of bones have been published by Dr. 

 Mantell in his ' Wonders of Geology,' vol. i. pi. i.; but, excepting the remark 

 above quoted, with regard to the nearer approach which the fossil makes in 

 the form of its teeth to the sub-genus Crocodilus, as compared with the more 

 slender Wealden tooth, no other observation has been published which tends 

 to establish more precisely and closely the true affinities and nature of the 

 Swanage Crocodilian. 



The first character which attracts attention is that which the numerous, 

 large, bony, dermal plates or scutes afford. These are scattered irregularly 

 over the slab, and in their number and relative size bring the species much 

 nearer to the extinct Teleosaurs thaii to any of the existing Crocodiles ; they 

 differ, however, from both the dorsal and ventral scutes of the Teleosaur in 

 their more regular quadrilateral figure ; they are longer in proportion to their 

 breadth than most of the Teleosaurian scutes, and are distinguished from 

 those of all other Crocodilians, recent and fossil, that I have yet seen, by the 

 presence of a conical, obtuse process, continued from one of the angles verti- 

 cally to the long axis of the scute, analogous to the peg or tooth of a tile, and 

 fitting into a depression on the under surface of the opposite angle of the 

 adjoining scute ; thus serving to bind together the plates of the imbricated 



* " On trouve parmi ces os dii Jura une petite dent pointue et tin pen tranchante, fort 

 semblable a celle du Crocodile de Caen," I. c. ix. p. 283, pi. ccxxxiv. fig. 8, i. e, the Teleo- 

 saurus Cadomensis, the teeth of which are " longues, greles, arquees, et tres-pointues, mais 

 non pas tranchantes." Ibid. p. 271. Cuvier then proceeds to say, " Mais il y en a aussi de 

 beaucoup plus grosses et plus obtuses, telles que celle de la fig. 7, qui pourraient annoucer 

 une autre espece." Ibid. p. 283. It is with tliis other species that the blunt-toothed Croco- 

 dilian of the Wealden and Purbeck limestone bears most resemblance. 



