How sessile are sea anemones? A review of free-living forms in the actiniaria (Cnidaria : Anthozoa)

There is scattered information in the literature that sea anemones are not always sedentary but instead may temporarily or permanently live loosely at tached, detached or even pelagically. This is the first attempt to summariz e and assess these observations and their probable ecological significance for the life cycles of the respective species. According to current knowled ge there are no truly pelagic species of sea anemones; thus, the 'Minyadida e' (sensu CARLGREN, 1949) have to be abolished as a taxonomic group. Instea d, there are indications that there are phases and stages within the life c ourse of many anemone species which are liable to lead a free life in respo nse to abiotic and biotic environmental factors. Juvenile, post-metamorphic stages seem to be of major significance in these respects and may be subje cted to long distance dispersal. It is speculated that some of these free-l iving stages may represent morphologically and/or ecologically different st ages between larvae and adults. The newly discovered lifestyle of 'straying predator' is described from sublittoral habitats off South Africa.