[602] Procœlian, concave before: amphicœlian, concave at both ends platycœlian, flat in front and concave behind.
[603] See Quart. Geol. Journ. vol. v. p. 380, pl. x.
Lign. 216. Skull and Jaws of Teleosaurus. 1/8 nat.
Lias. Whitby.
| Fig. | 1.— | Upper view of the cranium of Teleosaurus. c, occipital condyle. t, t, temporal fossæ. o, o, orbits. n, nasal apertures. |
| 2.— | Muzzle or anterior extremity of the jaws of Steneosaurus. | |
| 3.— | The same of Teleosaurus. | |
| 4.— | Lateral view of the cranium and lower jaw of Teleosaurus. |
With this exception, the Crocodilians with broad muzzles, as the Cayman and Alligator, have no representatives below the Tertiary formations; the Crocodilia of the Secondary deposits being all referable to the division having elongated beaks, like the recent Gavials (Bd. p. 250). The fossil Crocodiles of the latter type are arranged in two genera; namely, Teleosaurus[604] ([Lign. 216], fig. 3), in which the nasal apertures terminate in two orifices, (not blended into a single opening as in the recent species,) in front of the nose; and Steneosaurus ([Lign. 216], fig. 2), in which the breathing canals end in two nearly semicircular vertical openings at the extremity of the muzzle. (See also Bd. pl. xxv.)
[604] The skeleton of a recent Gavial, and that of a Teleosaur, are represented on one plate, for comparison, in Prof. Owen’s Monograph, loc. cit.
The British fossil species, most nearly related to the recent, occur in the Lower and Middle Eocene of the South-East of England. Two fine specimens of the skull of Crocodilus toliapicus, Cuvier and Owen (C. Spenceri of Dr. Buckland), have been found at Sheppey, as well as a skull of C. champsoïdes (Owen), and numerous vertebræ referable to each species. The eocene deposits of Hordwell Cliff have yielded the Crocodilus Hastingsiæ,[605] and the Alligator Hantoniensis (Petrif. p. 467; and Charlesworth's Geol. Journ. pl. i.); and the remains of a Gavial (Gavialis Dixoni, Owen, in Dixon’s Foss. Suss.) have been found at Bracklesham.[606]
[605] This fossil Crocodile supplies a good illustration of the biconvex body of the first caudal vertebra already described as peculiar to these loricated reptiles, see page 656; and I have subjoined [Lign. 217] in illustration of this structure.