Evolution

FROM THE GENERAL PREFACE: This multivolume work, The Mollusca, had its origins in the mid 1960s with the publication of two volumes entitled Physiology of Mollusca and edited by Wilbur and Yonge. In those volumes, 27 authors collaborated to summarize the status of the conventional topics of physiology as well as biochemistry, reproduction and development, and ecology. Within the past two decades, there has been a remarkable burgeoning of molluscan research generally and with it the development of new fields of investigation. During the same period, several excellent books on molluscs have appeared. However, they do not provide adequate information on the many recent advances or give the breadth of perspective of current knowledge of the phylum. Clearly, there was need for a larger work with a comprehensive treatment of major areas of molluscan research. The Mollusca, as a series of 12 volumes, attempts to fulfill this objective. Even here, practical considerations have meant that certain aspects of molluscan research have not been included.Each major area is treated by several authors, each reviewing his or her special field. The areas are structure and function, metabolic biochemistry, molecular biomechanics, environmental biochemistry, physiology, ecology, reproduction and development, neurobiology and behavior, and evolution. Throughout, the authors have given emphasis to recent advances and present status of molluscan biology. In so doing, directions of future research have become evident.The Mollusca is intended to serve several disciplines--zoology, biochemistry, physiology, and paleontology. It will prove useful to researchers and to all others with interests in molluscs.FROM THE PREFACE TO VOLUME 10: Recent events that have stimulated a great surge of investigation into the evolution of the Mollusca include the discovery of well-preserved microscopic molluscs at most levels of the Cambrian on five continents, the development of electron microscopy, the need to examine competing models of the early history of the phylum, new interest in interstitial fauna of littoral and near-littoral sands, and significant advances in our knowledge of shell ontogeny, construction, and evolution. It is timely that an up-to-date synthesis involving both paleontologists and zoologists should be published after a decade of such activity and advance when many of the long-held views on molluscan phylogeny have been overturned.This book deals with all molluscan classes except the Cephalopoda, which will be treated in Volume 12. The two books together provide an up-to-date introduction to the evolution of the Mollusca with adequate references to guide further work. They will be invaluable to specialists on molluscs, postgraduate research workers, and undergraduates with particular interests in this phylum. Authorities on the various molluscan groups were asked to express their views and to treat the subject as they wished; the book provides a valuable record of their opinions at this time.While the main groups are broadly and fully treated, focus has been narrowed toward a few selected minor groups of particular interest such as limpets, land snails, and the Anomalodesmata, in which recent work has been particularly significant.Because recent years have seen major revisions in classificatory terms, the editors have provided an outline classification into which the chapter topics fit.