ON BRITISH FOSSIL REPTILES. 67 



' Ft. In. Ln. 



From the orbit to the nostril 14 6 



Breadth of the cranium across the orbits 7 6 



Ditto five inches in advance of orbit 3 8 



Ditto across the first expansion of the jaw 4 



Ditto across the nostril , 2 8 



Depth of lower jaw at the posterior vacuity 3 6 



Length of the vacuity 3 



Breadth of the base of a tooth at the first expansion 8 



In the museum of Fr. Dixon, Esq., at Worthing, there is a fine fossil, re- 

 ferable to the Crocodilus Spenceri, from the Eocene clay of Bognor. It 

 consists of a portion of the skeleton, including the lumbar, sacral, and five 

 of the caudal vertebras, in a continuous chain of ten inches in length, but 

 bent in an abrupt curve. 



The vertebras, as compared with those of the Crocodilus acutus, have the 

 sides of the centrum deeper or more extended vertically, and they are slightly 

 concave ; the first caudal is, as usual, bi-convex, the under surface is rather 

 flattened. The femur presents the usual sigmoid curve, it has a well-marked 

 medullary cavity ; its length is five inches six lines. Mr. Dixon possesses, 

 from the same locality, a posterior cervical vertebra of a Crocodile, similar in 

 general characters to those just described, but larger, and probably belong- 

 ing to an older individual. The length of the body of this vertebra is two 

 inches and a half. 



Remains of Crocodilians occur in the London clay at Hackney, and in the 

 Eocene sand-beds at Kyson, in Suffolk ; I have seen from this locality small 

 bifurcate finely-striated conical teeth, and a small bony scutum, with regular 

 and pretty deep pits, about the size of pins' heads. 



/3. With biconcave Vertebrce. 



SUCHOSAURUS CULTRIDENS. 



Gavial of the Tilgate Forest, Mantell. (?) 

 Teleosaurus , H. v. Meyer. 



I next proceed to notice the fossil Crocodiles from the more recent second- 

 ary formations, and shall commence with those species with biconcave verte- 

 briB, the remains of Avhich are characteristic of the Wealden beds. 



Amongst the evidences of Crocodilian Reptiles which are scattered through 

 the Tilgate strata the most common ones are detached teeth, from the differ- 

 ence observable in the form of which. Dr. Mantell has observed, that " they 

 appear referable to two kinds ; the one belonging to that division of Croco- 

 diles with long slender muzzles, named Gavial; the other to a species of Cro- 

 codile, properly so-called, and resembling a fossil species found at Caen *." 



Dr. Mantell has obligingly communicated to me figures of well-preserved 

 specimens of both the forms of teeth alluded to, the exactness of which I 

 have recognized by a comparison with the specimens themselves in the 

 British Museum. 



The tooth which, from its more slender and acuminated form, approaches 

 nearest to the character of those of the Gavial, differs from the teeth of any 

 of the recent species of that sub-genus of Crocodilians, as well as from those 

 of the long and slender-snouted extinct genera, called Teleosaurus, Steneo- 

 saurus, &c. I have described this form of tooth fj therefore, as indicative 



* Wonders of Geology, 1839, vol. i. p. 386. 

 t Odoutography, pi. Ixii. A, figs. 9 and 10. 



f2 



