

World Hydrozoa database comes from a list of accumulated taxonomic information assembled over the years from the literature of Wim Vervoort and Peter Schuchert (see Schuchert, 1989). The list of the Siphonophorae was provided by Gill Mapstone who also manages the species of this Order. The number of known hydrozoan species is about 3800, although the status of many nominal species is currently unclear. A considerable number of names also represent synonyms.