130 BRITISH FOSSIL REPTILES. 



characters of the genus Gavialis. These characters are, however, participated in by 

 some of the extinct Crocodihans of the secondary strata (see PI. 1, fig. 2') ; but in 

 them they coexist with a different type of vertebra from that of the recent and known 

 tertiary Crocodihan genera : it became necessary, therefore, to ascertain what form of 

 vertebra might be so associated with the fossil Gavial-like jaws and teeth in the 

 Bracklesham Eocene deposits, as to justify the conchision that such vertebrae had 

 belonged to the same species as the jaws. Now, the only Crocodilian vertebrse that 

 have yet been found at Bracklesham, so far as I can ascertain, present the procoelian 

 type of articular surfaces of the body (PI. 3^), like that in Mr. Dixon's collection 

 fig. 8. This vertebra answers to the fifth cervical vertebra in the existing Crocodihans, 

 and accords in its proportions with that in the Gangetic Gavial. There are a few 

 indications of specific distinction ; the parapophysis {p) or lower transverse process 

 articulating with the head of the rib, is relatively shorter antero-posteriorly. The 

 broad, rough, neurapophysial sutures {n) meet upon the middle of the upper part of 

 the centrum ; the elsewhere intervening narrow neural tract sinks deeper into the 

 centrum than in the modern Gavial, but is perforated, as in that species, by the two 

 approximated vertical vascular fissures. The hypapophysis {hs) or process from the 

 inferior surface of the centrum, has been broken oiF in the fossil, but it accords in its 

 place and extent of origin with that in the fifth and follo\raig cervical vertebrse of the 

 Gavial. Assuming the fossil procoelian vertebrae from Bracklesham, and the above- 

 described vertebra in particular, to have belonged to the same individual or species as 

 the portions of fossil jaw (figs. 1, 5), then these mandibular and dental fossils must be 

 referred to the genus Gavialis, or to the long-, slender-, and subcylindrical-snouted 

 Crocodilia with procoelian vertebrae. 



This genus is now represented by one or two species peculiar to the great rivers 

 of India, more especially the Ganges ; and the fossil difi'ers from both the Gavialis 

 ffaiiffeticus, Auct., and from the (perhaps nominal) Gavialis tcnuirostris, Cuv., in the 

 form and relative size of the teeth. The crown (figs. 6, 7) is less slender in the fossil 

 than in the existing Gavials, and less compressed, its transverse section being nearly 

 circular. There are two opposite principal ridges, but they are less marked than in 

 the existing Gavials ; and are placed more obliqviely to the axis of the jaw, i. e., the 

 internal ridge is more forward, and the external one more backward, when the tooth 

 is in its place in the jaw. In the modern Gavial, the opposite ridges, besides being 

 more trenchant, are nearly in the same transverse line. The other longitudinal ridges 

 on the enamel of the fossil teeth, are more numerous, more prominent, and better 

 defined, than in the existing Gavials : the intermediate tracts of enamel present the 

 same fine wrinkles in the fossil as in the existing Gavials' teeth. 



The two chief portions of jaw (fig. 1, and figs. 4, 5) belong to two individuals of 

 different ages ; indicated by the difference in the breadth and depth of the ramus : 

 both specimens being from the corresponding part of the jaw, viz. where it forms the 



