More than two thirds of all living organisms described to date belong to the phylum Arthropoda. But their diversity, as measured in terms of species number, is also accompanied by an amazing disparity in terms of body form, developmental processes, and adaptations to every inhabitable place on Earth, from the deepest marine abysses to the earth surface and the air. The Arthropoda also include one of the most fashionable and extensively studied of all model organisms, the fruit-fly, whose name is not only linked forever to Mendelian and population genetics, but has more recently come back to centre stage as one of the most important and more extensively investigated models in developmental genetics. This approach has completely changed our appreciation of some of the most characteristic traits of arthropods as are the origin and evolution of segments, their regional and individual specialization, and the origin and evolution of the appendages. At approximately the same time as developmental genetics was eventually turning into the major agent in the birth of evolutionary developmental biology (evo-devo), molecular phylogenetics was challenging the traditional views on arthropod phylogeny, including the relationships among the four major groups: insects, crustaceans, myriapods, and chelicerates. In the meantime, palaeontology was revealing an amazing number of extinct forms that on the one side have contributed to a radical revisitation of arthropod phylogeny, but on the other have provided evidence of a previously unexpected disparity of arthropod and arthropod-like forms that often challenge a clear-cut delimitation of the phylum.

This volume contains the Proceedings of the Third International Conference on Copepoda, held at the British Museum (Natural History) in London during August 1987. The central theme of the conference was the biology of marine planktonic copepods, although the scientific programme was extremely varied reflecting the wide range of life styles adopted by copepods. The three invited symposia held during the conference focussed attention on particular topical areas of research within the field of marine plankton, and also provided reviews of chosen aspects of copepod biology. These symposia were highly successful. The papers they contained were both informative and stimulating and they bring to this volume a lasting significance. Each symposium was organised by its chairman; Bruce Frost (University of Washington) decided on the balance of topics, selected the speakers and introduced the session on 'The biology and taxonomy of Calanus', Roger Harris (Marine Biological Association) performed the same vital role for 'Experimental studies: rate processes in field populations of planktonic copepods', and Howard Roe (Institute of Oceanographic Sciences) for 'Oceanic and deep-sea copepods'. The impact of these papers will be much enhanced by the large number of high quality contributed and poster papers on marine plankton and by the invited review of 'Copepod luminescence' by Peter Herring (Institute of Oceano graphic Sciences). The fascinating review of 'Copepod eyes' by Mike Land FRS (University of Sussex) is not published here."

More than two thirds of all living organisms described to date belong to the phylum Arthropoda. But their diversity, as measured in terms of species number, is also accompanied by an amazing disparity in terms of body form, developmental processes, and adaptations to every inhabitable place on Earth, from the deepest marine abysses to the earth surface and the air. The Arthropoda also include one of the most fashionable and extensively studied of all model organisms, the fruit-fly, whose name is not only linked forever to Mendelian and population genetics, but has more recently come back to centre stage as one of the most important and more extensively investigated models in developmental genetics. This approach has completely changed our appreciation of some of the most characteristic traits of arthropods as are the origin and evolution of segments, their regional and individual specialization, and the origin and evolution of the appendages. At approximately the same time as developmental genetics was eventually turning into the major agent in the birth of evolutionary developmental biology (evo-devo), molecular phylogenetics was challenging the traditional views on arthropod phylogeny, including the relationships among the four major groups: insects, crustaceans, myriapods, and chelicerates. In the meantime, palaeontology was revealing an amazing number of extinct forms that on the one side have contributed to a radical revisitation of arthropod phylogeny, but on the other have provided evidence of a previously unexpected disparity of arthropod and arthropod-like forms that often challenge a clear-cut delimitation of the phylum.