DESCRIPTION OF REPTILES. 207 
Alligators, least so, perhaps, in Alligator palpebrosus, but is narrower and more 
tapering in most Crocodiles ; and in some species, as e.g. Croc. acutus and Croc. 
Schlegelii, the jaws are lengthened as well as attenuated, and indicate a transi- 
tion to the Gavials. In this genus (Gavialis) the jaws are very long and slender, 
their alveolar borders almost straight; the teeth are nearly equal in size and 
similar in form, and the first as well as the fourth teeth in each ramus of the 
lower jaw pass into notches in the border of the upper jaw when the mouth is 
shut. The symphysis of the lower jaw is of extreme length, its transverse sec- 
tion almost semicircular, and, as the corresponding part of the upper jaw pre- 
sents a similar form, the elongated muzzle is characterised as ‘ cylindrical.’ 
Genus CrocopiLus, Merrem. 
Species. Crocodilus Spenceri. 
Remains of extinct species of true Crocodiles (Crocodilus, Merrem) have been 
discovered at Sheppey, Bognor and Hordle. Mr. Dixon possesses good examples 
of the Crocodilus Spenceri from the two former localities ; and the Marchioness 
of Hastings has almost perfect specimens of the crania of the Crocodilus Has- 
tingsie, from the Hordle Cliff. Dr. Mantell* has alluded to a fossil Alligator 
found in the Hordle Cliff, but I have not yet seen any specimen, description or 
figure manifesting the characters and determining the existence of the American 
genus of Crocodilia (Alligator or Champsa) in British eocene strata. 
The specimen of Crocodilus Spenceri, from Bognor, in Mr. Dixon’s museum, 
consists of a chain of eight vertebra, including the sacral and characteristic 
biconvex first caudal, which are represented of their natural size in Tab. XV. 
fig. 1. A dorso-lateral bony scute (fig. 2) adheres to the same mass of clay close 
to the vertebrae, and doubtless belonged to the same individual. This fine 
specimen was discovered, and presented to Mr. Dixon, by the Rev. John Austin, 
M.A., rector of Pulbrough, Sussex. Fig. 3 is a rolled specimen of the anterior 
caudal vertebra of a large example of the Crocodilus Spenceri, from Sheppey. 
* « The only vestige of any other order of Reptiles observed in these strata is a tooth of the Cro- 
codilian type, apparently of the Alligator Hantoniensis, a fossil species described by Mr. Searles Wood 
from a splendid specimen of the lower jaw and teeth, found in the freshwater beds at Hordwell Cliff 
on the Hampshire coast.’— Geological Excursions round the Isle of Wight, 8vo, 1847, p. 115. 
22 
