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Ascidians are the invertebrate group that gave rise to vertebrates, thus the biology of ascidians provides an essential key to understanding both invertebrates and vertebrates. This book is the first to cover all areas of ascidian biology, including development, evolution, biologically active substances, heavy metal accumulation, asexual reproduction, host-defense mechanisms, allorecognition mechanisms, comparative immunology, neuroscience, taxonomy, ecology, genome science, and food science. The 69 articles that make up the collection were contributed by leading ascidiologists from all over the world who participated in the First International Symposium on the Biology of Ascidians, held in June 2000 in Sapporo, Japan. For scientists and students alike, the book is an invaluable source of information from the latest, most comprehensive studies of ascidian biology.

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´1. Fertilization and Egg Activation.- Structural and Molecular Investigations on the Egg Coat in Phallusia mammillata.- Analysis of the Self-sterility in Halocynthia roretzi.- Further Observations on the Molecular Bases of Gamete Self-discrimination in Ciona intestinalis: Seasonal Variation of Self-sterility Rate.- Self-nonself Recognition and Lysin System in Fertilization of the Ascidian Halocynthia roretzi.- Fertilization-induced Glycosidase Release and Interspecific Sperm Competition in Ascidians.- Cell Signaling in Ascidian Sperm: Upstream and Downstream of Internal Calcium Release.- Sperm-triggered Calcium Oscillations at Fertilization.- Diversity of Calcium Channels Involved in Meiosis Resumption of Ascidian Oocytes.- Ascidian Sperm Acrosin and Spermosin: Structures and Roles in Fertilization.- Acrosome Differentiation in Ciona intestinalis Spermatozoa and Some Speculations on Ascidian Fertilization.- Follicle Cells of Styela plicata Eggs (Ascidiacea).- High Level of Protein Ubiquitination in Ascidian Sperm.- Calcium Transients Signal Ooplasmic Segregation through the Small GTPase rho in Ascidian Eggs.- Cell Signalings for Activation of Motility and Chemotaxis in the Sperm of Ciona.- Roles of MLCK and PI3 Kinase on Deformation and Ooplasmic Segregation at Fertilization in the Egg of Ciona savignyi.- Identification of Phallusia mammillata Egg ?-N-Acetylhexosaminidase with a Potential Role in Prevention of Polyspermy.- The "Complex" Ascidiosperm of Aplousobranchs.- 2. Reproductive Biology and Neuroscience.- The Origin of Germ Cells in Ciona intestinalis.- Oocyte Maturation and Self-sterility by Treatment with Ovary Extracts of the Ascidian, Halocynthia roretzi.- Induction of Gamete Release by Gonadotropin-Releasing Hormone (GnRH) in Ciona intestinalis.- Light Regulated GnRH Neurons in Biological Clock for Reproduction in the Ascidian, Halocynthia roretzi.- Tailbud Embryogenesis and the Development of the Neurohypophysis in the Ascidian Ciona intestinalis.- The Peripheral Nervous System of an Ascidian Revealed by AChE Activity.- Heterotrimeric G Protein ? and ? Subunit Genes of the Ascidian, Halocynthia roretzi.- Photoresponse and Habituation of Swimming Behavior of Ascidian Larvae, Ciona intestinalis.- Multiple cis-Regulatory Regions Control Neuronal Gene Expression of Synaptotagmin in Ascidian Embryos.- 3. Development, Differentiation, and Evolution.- Maternal Genetic Information Stored in Fertilized Eggs of the Ascidian, Halocynthia roretzi.- RNA-binding Proteins in Ascidian Development.- Functional Analysis of Ciona intestinalis Y-Box Protein.- Ci-sna cis-Regulation of Ascidian Tail Muscle Genes.- T-box Genes and the Development of Axial Tissues in Ciona intestinalis.- Cloning and Embryonic Expression of HrzicN, a Zic Family Gene of the Ascidian Halocynthia roretzi.- Analysis of a cis-Regulatory Element of Hroth, the Ascidian Homologue of the otx Genes, That Drives Its Transcription in the Anterior Larval Central Nervous System of the Ascidian, Halocynthia roretzi.- Comparison of the Structure and Expression of otx Genes between Ciona intestinalis and Halocynthia roretzi.- Phylogeny of the Urochordates: Implications for Chordate Evolution.- Evolution of Anural Developmemt in Ascidians: Roles of Muscle-Specific Differentiation Genes.- Maximum Direct Development and the Ascidiotypic Stage.- The Origin of the Neural Crest and Insights into Evolution of the Vertebrate Face.- Participation of Neurotransmitters and Adrenergic Receptor in the Metamorphosis of Ascidian Larvae.- 4. Taxonomy and Ecology.- A Global Overview of Ascidian Introductions and Their Possible Impact on the Endemic Fauna.- Settlement and Metamorphosis of the Tropical Ascidian Herdmania curvata.- Ascidians in Brazil: The State of the art of Research in Taxonomy, Ecology and Natural Products.- The Biological Substratum Eudistoma carolinense Van Name, 1945 in t

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