Fig. 1. "A fossil body resembling part of a Tortoise, from Gloucestershire."--_Mr. Parkinson._ This specimen is probably one of the mandibles of a remarkable extinct genus (_Ceratodus_) of fishes, whose dental organs, like those of the recent _Chimæra_, consisted of consolidated plates instead of separate teeth; each side of the jaw was formed by one of these mandibular processes; the upper margin is deeply undulated. The bone-bed of the Lias at Aust Cliff near Westbury, Somersetshire, is rich in these remains. Fig. 2. The plastron, or inferior aspect of the carapace of a fossil Turtle (_Chelonia breviceps_), from the London Clay of the Isle of Sheppey. _a_, fragment of the _entosternal_ plate; _b, b_, _hyosternal_ plates; _c, c_, _hyposternals_; _d_, _xiphisternals_.[66] [Footnote 66: See Parkinson, p. 269.] Fig. 3. The cranium of the same species of Turtle, from the Isle of Sheppey. Equally rich in the remains of Chelonian reptiles, as in those of Fishes, Crustaceans, Serpents, and Mollusks, the little Island at the mouth of the Medway has yielded to the indefatigable researches of Mr. Bowerbank the most extensive series of fossil Turtles hitherto discovered in England. The various genera and species will be figured and described in a work now in progress by Professors Bell and Owen, under the auspices of the Palæontographical Society. Fig. 4. A Serpula (_S. antiquata ?_), from the chalk, Sussex. Fig. 5. A dorsal vertebra of a fossil crocodilian reptile (_Steneosaurus_), from the Oxford Clay of Honfleur. _a, b_, costal depressions. Fig. 6. A dorsal convexo-concave vertebra of a crocodilian or gavial-like reptile (_Streptospondylus_), from the same locality. This figure shows the remarkable character whence the name of this genus: the convexity of the body of the vertebra (_a_) being situated anteriorly as in mammalia, the reverse of the position of the bones forming the vertebral column in the existing Crocodilians and Lacertians. _b_, the posterior concavity; _c_, a deep depression beneath the neural arch. Fig. 7. Sketch of the lower jaw of an extinct gavial-like reptile (_Steneosaurus_): the vertebra, fig. 5, probably belongs to the same species. From Honfleur. This figure, and figs, 5, 6, and 8, are copied from Cuvier, "_Annales du Muséum_" Fig. 8. A caudal vertebra of the Fossil Animal of Maestricht (_Mosasaurus_); a, the chevron bone or inferior spinous process (_hœmapophysis_), anchylosed to the middle of the body of the vertebra. Fig. 9. Fossil scale of a ganoid fish (probably _Lepidotus_), from Kent.