contain the remains of Trilobites;[1] so that, during the long periods that intervened between the deposition of the earliest fossiliferous strata and the termination of the Coal formation,[2] the Trilobites appear to have been the chief representatives of a class which was largely multiplied into other orders and families, after these earliest forms of marine Crustaceans became extinct.
The fossil remains of this family have long attracted attention, from their strange peculiarities of configuration. M. Brongniart, in his valuable History of Trilobites, 1822, enumerated five genera,[3] and seventeen species; other writers (Dalman, Wahlenberg, Dekay, and Green,) have added five more genera, and extended the number of species to fifty-two; examples of four of these genera are given in Plate 46. Fossils of this family were long confounded with Insects, under the name of Entomolithus paradoxus; after many disputes respecting their true nature, their place has now been fixed in a separate section of the class Crustaceans, and although the entire family appears to have been annihilated at so early a period as the termination of the Carboniferous strata, they nevertheless present
- ↑ In Scotland two genera of Entomostracous Crustaceans, the Eurypterus, and Cypris, occur in the Freshwater limestone beneath the Mid Lothian Coal Field; the Eurypterus at Kirkton, near Bathgate, and the Cypris at Burdiehouse, near Edinburgh. (Trans. Royal Soc. Edin. vol. xiii.) The third Genus, Limulus, has but recently been recognised in the Coal Formation, and will be described presently. The Entomostracans appear to have been the only representatives of the Class Crustaceans until after the deposition of the Carboniferous strata.
- ↑ Trilobites of a new species have lately been found in Ironstone from the centre of the coal measures in Coalbrook-dale. Lond. and Edin. Phil. Mag. vol. 4. 1834, p. 376.
- ↑ The names of these Genera are Calymene, Asaphus, Ogyges, Paradoxus, and Agnostus. Some of these terms are devised expressly to denote the obscure nature of the bodies to which they are attached; e.g. Asaphus, from ἀσαφης, obscure; Calymene, from κακαλυμμένη, concealed; παράδοξος, wonderful; ἀγνωστος, unknown.
