The Embryology of the Echiuroid Worm Urechis Caupo

xv, 219 pp. CONTENTS: Preface and Acknowledgments; Introduction; Reproductive System and Germ Cells of Urechis; Material and Methods Used in the Embryological Investigation; Development of Urechis; Gastrulation and Shifting of Embryonic Areas and Axes; Organogenesis; Comparison of the Development of Urechis with that of Other Echiuroids; Comparison of Echiuroid Development with that of Other Invertebrates; The Phylogenetic Position of the Echiuroidea; Bibliography.