• Hydractinia (Stylactis) Allman, 1864 accepted as Stylactis Allman, 1864
• Hydractinia (Stylactis) ingolfi Kramp, 1932 accepted as Hydractinia ingolfi (Kramp, 1932)
• Stylactella (Stylactis) Allman, 1864 accepted as Stylactis Allman, 1864
• Stylactella (Stylactis) yerii Iwasa, 1934 accepted as Hydractinia yerii (Iwasa, 1934)
• Stylactis Allman, 1864
• Stylactis affinis Jäderholm, 1904 accepted as Perarella affinis (Jäderholm, 1903)
• Stylactis arctica Jäderholm, 1902 accepted as Hydractinia arctica (Jäderholm, 1902)
• Stylactis arge Clarke, 1882 accepted as Hydractinia arge (Clarke, 1882)
• Stylactis betkensis Watson, 1978 accepted as Hydractinia betkensis (Watson, 1978)
• Stylactis brachyurae Hirohito, 1988 accepted as Hydractinia brachyurae (Hirohito, 1988)
• Stylactis carcinicola Hiro, 1939 accepted as Bouillonactinia carcinicola (Hiro, 1939)
• Stylactis claviformis Bouillon, 1965 accepted as Hydractinia claviformis (Bouillon, 1965) accepted as Hydractinia proboscidea (Hincks, 1868)
• Stylactis conchicola Yamada, 1947 accepted as Schuchertinia conchicola (Yamada, 1947)
• Stylactis fucicola (M. Sars, 1857)
• Stylactis fuciola (Sars, 1857) accepted as Stylactis fucicola (M. Sars, 1857)
• Stylactis halecii Hickson & Gravely, 1907 accepted as Rhysia halecii (Hickson & Gravely, 1907)
• Stylactis hooperi Sigerfoos, 1899 accepted as Stylactis hooperii Sigerfoos, 1899 accepted as Bouillonactinia hooperii (Sigerfoos, 1899)
• Stylactis hooperii Sigerfoos, 1899 accepted as Bouillonactinia hooperii (Sigerfoos, 1899)
• Stylactis hooperii var. minor Wedler & Larson, 1986 accepted as Bouillonactinia hooperii (Sigerfoos, 1899)
• Stylactis inabai Hirohito, 1988 accepted as Hydractinia inabai (Hirohito, 1988) accepted as Bouillonactinia misakiensis (Iwasa, 1934)
• Stylactis indica Stechow, 1920 accepted as Cytaeis indica (Stechow, 1920)
• Stylactis inermis Allman, 1872
• Stylactis ingolfi Kramp, 1932 accepted as Hydractinia ingolfi (Kramp, 1932)
• Stylactis minoi Alcock, 1892 accepted as Hydractinia minoi (Alcock, 1892)
• Stylactis misakiensis (Iwasa, 1934) accepted as Bouillonactinia misakiensis (Iwasa, 1934)
• Stylactis monoon Hirohito, 1988 accepted as Hydractinia monoon (Hirohito, 1988)
• Stylactis piscicola Komai, 1932 accepted as Hydractinia piscicola (Komai, 1932)
• Stylactis pruvoti (Motz-Kossowska, 1905) accepted as Hydractinia pruvoti Motz-Kossowska, 1905 accepted as Podocoryna pruvoti (Motz-Kossowska, 1905)
• Stylactis reticulata Hirohito, 1988 accepted as Schuchertinia reticulata (Hirohito, 1988)
• Stylactis sagamiensis Hirohito, 1988 accepted as Cytaeis sagamiensis (Hirohito, 1988)
• Stylactis sandrae Wedler & Larson, 1986 accepted as Hydractinia sandrae (Wedler & Larson, 1986)
• Stylactis spinipapillaris Hirohito, 1988 accepted as Hydractinia spinipapillaris (Hirohito, 1988)
• Stylactis spiralis (Goto, 1910) accepted as Hydractinia spiralis Goto, 1910
• Stylactis uchidai Yamada, 1947 accepted as Schuchertinia uchidai (Yamada, 1947)
• Stylactis vermicola Allman, 1888 accepted as Stylactella vermicola (Allman, 1888)
• Stylactis yerii Iwasa, 1934 accepted as Hydractinia yerii (Iwasa, 1934)