[446] This is the Astacus rostratus of Prof. Phillips’s Geol. York. vol. i. tab. 4, fig. 20.
A remarkable macrurous crustacean (Eryon Cuvieri) is found in the Jurassic limestone of Solenhofen. Perfect specimens of this species are occasionally seen in collections; it is distinguished by its very large, flat, oval shell, with the front lateral margins strongly dentated, and by its short setaceous antennæ; the front claws are as long as the body, and armed with pincers; the post-abdomen consists of six segments, terminating in a caudal appendage or tail.
In the United States several fossil crustaceans have been noticed in the Cretaceous strata of New Jersey; some of which are said to be related to Pagurus, and others to Astacus.
Fossil Prawns and Shrimps, of exquisite beauty, are found in the lithographic limestone of Pappenheim: a specimen from that locality (Palæmon spinipes) is figured Wond. p. 513: see also Frontispiece of this work.
A large crustacean of the Shrimp family has been discovered by the Earl of Enniskillen in the Lias of Lyme Regis.[447] Other specimens also of Macrura, more or less perfect, have been obtained from the same rich mine of organic remains: especially some in which the branchiæ, or respiratory organs, remain; and a portion of the post-abdomen, or tail, of a Cray-fish, as large as the common species.
[447] This beautiful fossil is figured and described by Mr. Broderip, Geol. Trans, second series, vol. v. pl. xii. under the name of Coleia antiqua.
FOSSIL ISOPODOUS CRUSTACEANS.
Isopodous Crustaceans. [Lign. 171].—Isopoda (equal-feet) is the term applied to an order of crustaceans in which the body is composed of a distinct head, and seven rings, each having a pair of equal feet; the common Oniscus, or wood-louse, is a familiar example of a terrestrial Isopod. This order includes many genera and species, some of which nearly approach the extinct family of crustaceans (Trilobites) whose remains abound in the palæozoic strata; and the parasitical Isopod, Bopyrus, that infests the common Prawn, is closely related to certain genera of Trilobites, hereafter described.