February issue includes Appendix entitled Directory of United States Government periodicals and subscription publications; September issue includes List of depo

FROM THE GENERAL PREFACE: This multivolume work, The Mollusca, had its origins in the mid 1960s with the publication of two volumes entitled Physiology of Mollu

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 de