About 95 per cent of all known animal species are invertebrates. A knowledge of their sexual, reproductive, and developmental biology is essential for the effective management of species that are economically useful to man or are harmful to him, his crops and livestock. This treatise is the first to cover all aspects of reproduction and development of the entire spectrum of invertebrates terrestrial, marine, fresh-water, brackish-water, free-living, and parasitic. The chapters, by leading world experts in their fields, are up-to-date and informative, and suggest a number of problems for future research. Progress in Developmental Endocrinology (issued in parts A and B) is the tenth Volume in the series. Volume X, Part A Progress in Developmental Endocrinology Edited by August Dorn Contents Preface to the Progress Series; Preface to Volume X A; Contributors; Endocrine Systems of Protostomia and Non-Vertebrate Deuterostomia An overview D. Buckmann; Porifera Werner E.G. Muller and Isabel M. Muller; Ctenophora and Cnidaria Cornelis J.P. Grimmelikhuijzen; Platyhelminthes Maria Reuter and Margaretha K.S. Gustafsson; Nematoda Klaus-Dieter Spindler and Margarethe Spindler-Barth; Mollusca Naokuni Takeda; Endocrine Disruption of Reproduction by Organotins in Mollusca Naokuni Takeda; Arthropoda Chelicerata Jean-Louis Connat, Arthropoda Crustacea Klaus-Dieter Spindler, Peter Jaros and Wolfgang Weidemann; Arthropoda Myriapoda Heinrich Scheffel; Subject Index; Species Index.