Lign. 242. Palæophis toliapicus: 2/3 nat. size.
London Clay. Isle of Sheppey.
Six concavo-convex vertebræ of the trunk.
FOSSIL SERPENTS.
VII. Ophidians, or Serpents. [Lign. 242].—The remains of the vertebral columns of extinct Serpents were discovered many years since in the London clay of the Isle of Sheppey, and specimens were obtained by the celebrated Hunter, and preserved in his museum. These specimens, together with others in the collections of Messrs. Saull, Bowerbank, Dixon, Combe, and S. Wood, have been figured and described, and their relations to existing types elaborately worked out, by Professor Owen.[692] The Palæophis typhæus, from the Bracklesham clay, had a length of about twenty feet, and, from the compressed character of its caudal vertebræ, was probably a sea-serpent. A somewhat smaller species also occurs at Bracklesham. The Sheppey specimens are referred to another species of this extinct genus, namely, the P. toliapicus ([Lign. 242]); it was from ten to twelve feet in length. The remains of two species of land-serpents, respectively about four and three feet long, have been found at Hordwell Cliff. These belong to the extinct genus Paleryx, thus named in reference to the near affinities of the Hordwell vertebræ to those of the recent Eryx, one of the Boa and Python group of serpents.[693]
[692] Geol. Trans. 2d ser. vol. vi. p. 209, &c. pl. xxii.; Rep. Brit. Assoc. 1841, p. 180; "Dixon’s Geology and Fossils of Sussex," pp. 211-217, pl. xii. fig. 14; and especially Palæontographical Monograph, 1850, p. 51, et seq.; and plates xii. to xvi.
[693] See Monograph on Eocene Reptiles, 1850, from which these notices of the Eocene Ophidians are abridged.
The vertebræ of Serpents are distinguished by a transversely oblong anterior concavity, forming a deep cup, and a corresponding posterior convexity or hall; by the interlocking of the projecting posterior oblique processes with the anterior pair; and by the oblong tubercle on each side of the anterior part of the body of the vertebra, for moveable articulation with the head of the ribs; a spinal column thus constructed combines in the highest degree perfect flexibility with great strength.
In addition to the ophidian relics above referred to, fossil vertebræ of a small serpent (Palæophis?) have been found in the Eocene sand below the Bed Crag, at Kyson in Suffolk;[694] a locality that has yielded other organic remains of great interest (see chap. xix.; and Wond. p. 258). The only fossils of this order of reptiles known to Baron Cuvier appear to have been some vertebræ from the bone-breccia of Cette (Oss. Foss. tom. iv. p. 177).
[694] Rep. Brit. Assoc. 1841, p. 181; and Monograph, 1850, p. 66.
Fossil eggs of snakes are occasionally met with in a comparatively recent limestone, of fresh-water origin, in Germany, near Offenbach, associated with shells of land and fresh-water molluscs. Like the turtles’ eggs on the shores of Ascension Island, these ova were probably laid in the moist mud, and became encrusted and preserved by a deposit of tufa.[695]