Fig. 19. "_Coronulites diadema._"--_Mr. Parkinson._ Probably a species of Balanus, from a tertiary deposit. Fig. 20. Cast of one of the shells of a bivalve (_Pentamerus_), from the Wenlock limestone of Dudley. [Illustration: Plate LXVIII.] PLATE LXVIII. Fossil Crustacea. Figs. 1, & 3. "Fossil Crabs, from Sheppey."--_Mr. Parkinson._ The London clay of this celebrated locality contains an abundance of the fossil remains of Crustacea; and the visitor may purchase of the local collectors fossil crabs and lobsters, as readily as the recent species from the neighbouring sea. Good specimens are however rare, and command high prices. The specimens figured are two common species. Fig. 1. _Cancer Leachii_, of MM. Desmarest and Brongniart. Fig. 3. _Inachus Lamarckii._ These fossils show the usual mode in which the crustaceæ occur in the hardened clay of Sheppey. The thorax is bent over the abdomen, and the pair of large chelate claws drawn towards each other. Fig. 2. Fossil Insects from the lithographic stone of Pappenheim. "_a_, an insect with a bifurcated caudal extremity; _b_, the sting which has passed out of its sheath; c, the termination in a single point."--_Mr. Parkinson._ Fig. 4. "A fossil Shrimp, from Anspach."--_Mr. Parkinson._ Fig. 5. "Impression of an unknown fossil."--_Mr. Parkinson._ Fig. 6. "The claw of a Crab, from Maestricht, &c."--_Mr. Parkinson._ Claws of this kind are frequent in the soft sandy limestone of St. Peter's Mountain, but no other vestiges of the Crabs to which they belonged have been met with. The cause of this has been ascertained: the claws belong to a species of Hermit Crab (_Pagurus Faujasii_, of Desmarest), which like the living species had the body covered by a delicate membrane, the claws only possessing a durable crustaceous shell.[64] [Footnote 64: Wonders of Geology, p. 338.]