There are many fields of research into adult benthic polychaetes where the study of their planktonic larvae is beneficial. These include the reproductive activity of adults from the larval period, the identification of hydrological and climatic conditions for benthic life, the interannual
fluctuations of benthic populations, the transfer of energy between plankton and benthos, settlement conditions at the benthic stage, variations in reproductive patterns with latitude, biogeographic implications of larval dispersion, larvae and evolutionary processes. It is clear from this
non-exhaustive list that, in dealing with planktonic larvae, the benthic part of the life cycle associated with development in the sediment or on hard substrates of the benthos is also involved. Consequently, results can be obtained over the whole life cycle by studying larvae. Examples of
such integration are provided which also reflect a change in hitherto accepted thinking. Three points are developed for polychaetes: (1) latitudinal variations in the pattern of reproduction; (2) contribution of planktonic larvae to the question of the existence of cosmopolitan species; (3)
reproduction at great depth. A new picture of the larval stage is evolving: the 'new' larva is not a passive object, and it covers an area that is probably more limited than previously thought; its characteristic features are connected with the other parts of the life cycle. Finally, it is
suggested that planktonic larvae, even those with a strong potential for dispersion, are not destined for widespread dissemination; they occupy a limited area, which results either from a reduction in their dispersion potential, or from control by the physical structures of the surrounding
The Bulletin of Marine Science is dedicated to the dissemination of high quality research from the world's oceans. All aspects of marine science are treated by the Bulletin of Marine Science, including papers in marine biology, biological oceanography, fisheries, marine affairs, applied marine physics, marine geology and geophysics, marine and atmospheric chemistry, and meteorology and physical oceanography.