A fi eld guide to the Silurian Echinodermata of the British Isles: Part 1 - Eleutherozoa and Rhombifera D.N. Lewis, S.K. Donovan, P. Crabb & D.J. Gladwell Lewis, D.N., Donovan, S.K., Crabb, P. & Gladwell, D.J. A fi eld guide to the Silurian Echinodermata of the British Isles: Part 1 - Eleutherozoa and Rhombifera. Scripta Geologica, 134: 27-59, 4 pls., 6 fi gs., 1 table, Leiden, March 2007. David N. Lewis, Department of Palaeontology, The Natural History Museum, Cromwell Road, London, SW7 5BD, England (
[email protected]); Stephen K. Donovan, Department of Geology, Nationaal Natuur- historisch Museum, Postbus 9517, NL-2300 RA Leiden, The Netherlands (
[email protected]); Philip Crabb, Photographic Unit, The Natural History Museum, Cromwell Road, London, SW7 5BD, England (
[email protected]); David J. Gladwell, Department of Geology, University of Leicester, Leicester, LE1 7RH, England (
[email protected]). Key words – Echinoderms, Silurian, British Isles, echinoids, asteroids, ophiuroids, cystoids, ophiocysti- toids. The Palaeozoic echinoderms of the British Isles are most diverse in the Silurian and Lower Carbonifer- ous. This guide discusses and illustrates members of all major groups of echinoderms, apart from the crinoids, from the Silurian of these islands. Groups considered include the echinoids (fi ve taxa), ophiuroids (ten taxa) and asteroids (thirteen taxa), and the extinct ophiocistioids (three species) and rhombiferan cystoids (nine species). Contents Introduction .............................................................................................................................................................