Contents. List of Contributors. Preface (P.M. Wassarman). The In Vivo Function of Müllerian-Inhibiting Substance During Mammalian Sexual Development (Y. Mishina and R.R. Behringer). The Role of the dpp-Group Genes in Dorsoventral Patterning of the Drosophila Embryo (C.Rushlow and S. Roth). The Terminal Gene Hierarchy of Drosophila and the Genetic Control of Tissue Specification and Morphogenesis (M.L.R. Yip and H.D. Lipshitz). Anterior-Posterior Polarization and Mesoderm Inducing Factors in the Pregastrula Mouse Embryo: Comparison to Chick and Frog Embryos (R.F. Bachvarova). Human Y Chromosome Function in Male Germ Cell Development (P.H. Vogt). Index.