Nutrition in the Lower Metazoa contains the proceedings of a meeting held at the University of Caen, France on September 11-13, 1979. Organized into 14 chapters, this book begins with a discussion of the phagocytosis in Polycelis tenuis and adaptational aspects in feeding in freshwater triclads. Subsequent chapters explore selection in sponge feeding processes; nutrition in symbiotic Turbellaria; some effects of diet on the biology of the rotifers; and the role of nutrition in the establishment of the green hydra symbiosis. The phosphorus economy of the green hydra symbiosis and the nutrition of marine sponges are also explained.

Cell signalling lies at the heart of many biological processes and currently is the focus of intense research interest. In multicellular organisms, it is central to how different types of cell communicate with each other and how they detect and respond to extracellular signals. Intercellular communication is vital to single-celled organisms as well, allowing them to respond to environmental cues and signals. To date, much of the understanding of signalling mechanisms has come from research on specific cell types (eg mouse lymphocyte and cardiomyocyte) or on organisms in which communication systems such as nervous and endocrine systems are well established. This volume therefore aims to 'fill the gap' by concentrating on 'simple organisms' where the elements of those signalling systems first evolved. Many of the groups covered contain important pathogens or parasites, and the potential for manipulating signalling pathways for therapeutic intervention will be highlighted.

Additional Contributor Is Willard D. Hartman.

Recently, new genes and their proteins that revealed striking new insights into the early evolution of multicellular animals have been identified and characterized from members of the lowest metazoan phylum, the porifera (sponges). The unexpected result was that the sequences obtained from sponge displayed high similarity to those found in higher metazoa; in consequence, it was concluded that during the transition from protozoa to metazoa the major structural and regulatory proteins evolved only once. The data gathered are now powerful arguments to establish monophyly of metazoa; in addition, new insights on the evolutionary diversification of metazoa were obtained.

Several years ago, we realized that the most prominent ideas that had been ex pressed about the origin and early evolution of the Metazoa seemed to have been developed chiefly by zoologists using evidence from modern species without reference to the fossil record. Paleontologists had, in fact, put forth their own ideas but the zoological and the paleontological evidence were about the problem, seldom considered together, especially by zoologists. We believed that the paleon tological documentation of the first Metazoa was too scattered, too obscure to Western readers, and much of it too recent to have been readily available to our colleagues in zoology. Whether or not that was entirely true, we thought that a single volume reviewing the fossil record of the earliest Metazoa would be useful to many in both paleontology and zoology, especially since so much new informa tion has been developed in the last few years. Some of this information has been summarized in general articles recently, but an overview of most of the field does not exist. We therefore organized this book in five parts so that the evidence could be placed in perspective and summarized and inferences made from it. Part I intro duces the previous hypotheses that have been proposed for the origin and early radiation of Metazoa. Part II consists of two summary chapters that set the sedi mentological, geochemical, and biological background to the known radiations of Metazoa.