On the Vertebral Column and Pelvic Bones of Pliosaurus Evansi (Seeley), from the Oxford Clay of St. Neotts, in the Woodwardian Museum of the University of Cambridge

Abstract

Knowing how many Plesiosaurian genera have left their remains in the great Pelolithic system formed by the Oxford Clay, Ampthill Clay, and Kimmeridge Clay, and that triangular teeth have not been obtained from the Oxford Clay of St. Neotts, some amount of indecision may be justifiable in the generic determination of this species. Nevertheless the cervical and dorsal vertebræ closely resemble in typical characters those of Pliosaurs from the Kimmeridge Clay; and I do not detect in them or in the pelvic bones indications of approximation to the known characters of any other genus. The remains are from the well-known pit in the lower part of the Oxford Clay at Eynsbury, near St. Neotts, which yields Ammonites Duncani, A. Lamberti, A. coronatus, &c . They comprise thirty-seven vertebræ in sequence, of which twenty are cervical and about sixteen dorsal; and there is one pubic bone and one ischium. But the vertebral bones were obtained at a former period, and the pelvic bones after an interval of some years. We owe the discovery and preservation of these fossils to J. J. Evans, Esq., of St. Neotts, who presented them to the University of Cambridge; and it is in honour of the discoverer that I propose the species should be named. The Atlas and Avis (figs. 1, 2). These vertebræ though in close contact, do not appear to have been ankylosed together. They have lost their neural arches, like all other Pliosaurian vertebrae. A large subvertebral wedge-bone beneath the atlas ( c ) projects for