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 unusually abundant store of these most essential organs.[1] As Crocodiles increase to no less than four hundred times their original bulk, between the period at which they leave the egg and their full maturity, they are provided with a more frequent succession of teeth than the mammalia, in order to maintain a duly proportioned supply during every period of their life. As the predaceous habits of these animals cause their teeth, placed in so long a jaw, to be peculiarly liable to destruction, the same provision serves also to renew the losses which must often be occasioned by accidental fracture.
The existence of these remedial forces, thus uniformly adapted to supply anticipated wants, and to repair foreseen injuries, affords an example of those supplementary contrivances, which give double strength to the argument from design, in proof of the agency of Intelligence, in the construction and renovation of the animal machinery in which such contrivances are introduced.
The discovery of Crocodilean forms so nearly allied to
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 terminated 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 associated, 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.
- ↑ This mode of dentition has been already exemplified in speaking of the dentition of the Ichthyosaurus, P. 136, and Pl. 11. A.
