Figs. 14, & 15, are the anchylosed caudal vertebræ of the tails of fishes. From the London clay, Isle of Sheppey. Fig. 16. "A small oyster with a spathose structure."--_Mr. Parkinson._ This shell is probably the flat valve of a species of _Dianchora_, of Sowerby; from the Chalk. [Illustration: Plate LXVI.] PLATE LXVI. Fossil Bivalve Shells. Fig. 1. A fossil Oyster (_Ostrea Marshii_, of Sowerby), from the Cornbrash of the Oolite, Wiltshire. Fig. 2. The fossil Cockscomb Oyster, (_Ostrea carinata_, of Lamarck,) from the Lower chalk, Havre, France. Fig. 3. The elegant fossil shell here figured is a peculiar and most abundant species in the Lias formation; specimens are not uncommon, in which every part of the shell is as perfect as if just thrown up on the sea-shore. It belongs to the genus Gryphites (_Gryphea incurva_, of Sowerby,) the shells of which are nearly related to the oysters, but are distinguished by the deep concave under-valve, and its curved beak, and the almost flat upper shell. The testaceous substance is of a finer laminated structure than in the Ostrea, and the hinge-ligament is inserted in an elongated curved groove.[61] [Footnote 61: Medals of Creation, vol. i. p. 387.] Fig. 4. "_Ostrea vel frons folium._"--_Mr. Parkinson._ This species appears to be the _Ostrea gregarea_ (?) of Sowerby, which occurs in the chlorite marl or firestone of the Lower chalk in Sussex and Kent. Fig. 5. The fossil is the cast of an oyster-like bivalve, called Perna, (_Perna quadrata_, of Sowerby,) which is easily recognisable, even in casts, by the line of distinct teeth which compose the hinge. This species is abundant in the Portland limestone, particularly in the quarries around Swindon, in Wiltshire; but from the close adhesion of the outer surface of the shell to the surrounding stone, they can seldom be extracted, the casts only being readily obtainable. In the Kimmeridge clay, which lies above the Portland rock, the shells may be met with in great perfection. The best locality is near Hartwell, in Buckinghamshire, where the clay is extensively dug for the brick manufactures. Figs. 6, & 7. Two views of a small shell of the genus _Crenatula_, from Bedfordshire. Fig. 8. Portion of a very large species of Perna (_Perna maxillata_, of Sowerby), from tertiary strata. Piedmont. The figure shows the inner surface of the shell with part of the broad crenulated hinge. [Illustration: Plate LXVII.] PLATE LXVII. Fossil Shells of Brachiopoda, &c.