CROCODILIA. 131 



long symphysis characteristic of the Gavials. The specimen (figs. 4, 5) includes a 

 larger proportion of the jaw than the fragment delineated in fig. 1. 



On comparing the latter fragment of the fossil lower jaw with a specimen of a 

 lower jaw of the Gavialis gangeticm of the same breadth across the symphysial part, 

 at the intervals of the sockets, which breadth is 3 centimeters (1 inch 3 lines), I find 

 that the longitudinal extent of 10 centimeters (near 4 inches) of a ramus of the fossil 

 jaw includes five sockets ; but in the recent Gavial the same extent of jaw includes 

 seven sockets, showing that the teeth are fewer as well as larger in the fossil Gavial, in 

 proportion to the breadth of the jaws. 



The second portion of the jaw (fig. 2) is from the part where the rami diverge 

 posteriorly from the symphysis, and near the posterior termination of the dentary 

 series. Here the teeth become shorter in proportion to their thickness, and somewhat 

 closer placed together : there is a shallow depression (e) in each interspace of the 

 teeth, for the reception of the crowns of the opposite teeth when the mouth is shut. 

 These depressions are longer, deeper, and better defined in the fossil than in the recent 

 Gavial of the same size. 



The fragments of jaw and teeth of the fossil Gavial of Bracklesham show examples 

 of young teeth penetrating the base of the old ones, according to the law of succession 

 and shedding of the teeth, which characterises the existing Crocodilia : fig. 2 shows the 

 apex of one of the successional teeth at d ; and fig. 3 d the hollow base of the same 

 incompletely formed tooth seen from below. 



Besides the fossil jaws, teeth, and vertebrae of the extinct Gavial, a nearly entire 

 femur (fig. 9) of a Crocodilian has been discovered in the Eocene deposits at 

 Bracklesham, which in its proportions, agrees with that bone in the Gavial of the 

 Ganges. Cuvier, in his comparison of the bones of the Gavial with those of the 

 Alligators and true Crocodiles, merely observes, "La forme des os du Gavial ressemble 

 aussi prodigieusement a celle des os du Crocodile, seulement les apophyses epineuses 

 des vertebres sont plus carrees."* 



With regard to the femur, this bone is more slender in proportion to its length in 

 the Gangetic Gavial, than in the Crocodihis hvporcatus or the AUi<jator liicius, and the 

 anterior convex bend of the shaft commences nearer the head of the bone ; and in these 

 characters the fossil femur from Bracklesham corresponds with the modern Gavial, and 

 differs from the Crocodiles and Alligators, and also from the Crocodihis Hmtingsice, of 

 which species specimens of the fossil femur have been kindly submitted to me by the 

 Marchioness of Hastings and Alexander Pytts Falconer, Esq. The fossil femur of the 

 Gavial from Bracklesham (fig. 9) may therefore be referred, with the utmost probability, 

 to tlic same species as the portions of jaw, teeth, and vertebrae above described ; and 

 as these clearly demonstrate a species distinct from any known Gavial, I propose to 

 call the extinct species of the Eocene deposits at Bracklesham, Gavialis Dixoni, after 



* Ossemens Fossiles, 4to, torn, v, pt. ii, p. 108. 



