CROCODILEANS. 253 
others, from the secondary and tertiary forma- 
tions in England remain to be described.* 
It would be foreign to our present purpose, to 
enter into a minute comparison of the osteology 
of living and fossil genera and species of this 
family. We may simply observe, with respect 
to their similar manner of dentition, that they 
all present the same examples of provision for 
extraordinary expenditure of teeth, by an un- 
usually abundant store of these most essential 
organs. t As Crocodiles increase to no less 
than four hundred times their original bulk, 
* One of the finest specimens of fossil Teleosauri yet disco- 
vered, (see PL 25, Fig. 1), was found in the year 1824, in the 
alum shale of the lias formation at Saltvvick, near Whitby, and 
is engraved in Young and Bird's Geological Survey of the York- 
* shire Coast, 2d Ed. 1828 : its entire length is about eighteen feet, 
the breadth of the head twelve inches, the snout was long and 
slender, as in the Gavial, the teeth, one hundred and forty in 
number, are all small and slender, and placed in nearly a straight 
line. The heads of two other individuals of the same species, 
found near Whitby, are represented in the same plate. Figs. 2. 3. 
Some of the ungual phalanges, which are preserved on the hind 
feet of this animal, Fig. 1 , show that these extremities were ter- 
minated by long and sharp claws, adapted for motion upon land, 
from which we may infer that the animal was not exclusively 
marine ; from the nature of the shells with which they are asso- 
ciated, in the lias and oolite formations, it is probable that both 
the Steneosaurus and Teleosaurus frequented shallow seas. Mr. 
Lyell states that the larger Alligator of the Ganges sometimes 
descends beyond the brackish water of the delta into the sea. 
t This mode of dentition has been already exemplified in 
speaking of the dentition of the Ichthyosaurus, P. 172, and PI. 
11. A. 
