Revision of the Hawaiian Stylasteridae (Cnidaria: Hydrozoa: Athecata)

Four species of stylasterids are described from the Northwestern Hawaiian Islands (Kure to KauaÔi) at depths of 293Ð583 m, including three new species: Distichopora asulcata, Stylaster griggi, and S. infundibuliferus. In addition, specimens of Distichopora anceps were observed and collected, showing it to be the most common macroinvertebrate on the northwestern slope of Laysan Island but not known from any other Hawaiian locality. Its description was amended to include branching colonies with up to 20 lobes; a suggested ontogeny of these growth forms is illustrated. Also, unique sexually dimorphic features of both male and female ampullae of D. anceps are described.