Multicellular Animals

Those who wish for permanence in classifi cation must pay the price of stasis - as if for ever condemned to confound whales with fish. M. T. Ghiselin 1981, p. 283 Scientific argument is a debate concerned with the solution of unresolved problems. Before continuing with the phylogenetic system of the Metazoa this foreword gives me the opportunity to discuss some controversial ques tions, to state selected positions more precisely and to remedy omissions. I would like to draw special attention to serious problems for phylogenetic systematics resulting from the inevitable confrontation with the current rules of nomenclature 1. In carrying out this debate, I hope not to lose the goodwill of those readers who are experts within the first few pages. A textbook for students? - Critics who ask that question and answer in the negative probably underestimate the open-mindedness of young people who are not troubled by, or can easily free themselves from, the restraints and arbitrariness of traditional classifications - and to whom systematics is offered as a scientific product in such a form that arguments for every single decision are comprehensible and checkable and can therefore be fully analyzed.