Hydromedusae observed during night dives in the Gulf Stream Author Schuchert, Peter Muséum d’histoire naturelle, C. P. 6434, CH- 1211 Genève 6, Switzerland peter.schuchert@ville-ge.ch Author Collins, Richard 880 NE 33 rd Street, Boca Raton, Florida, USA rc6684@icloud.com text Revue suisse de Zoologie 2021 2021-10-21 128 2 237 356 journal article 3356 10.35929/RSZ.0049 172fa5c5-c0c4-4bd7-b710-d608237b8458 0035-418 5639938 8382D1CA-7C0E-4B1C-9591-4CEAA2F296FB Genus Staurodiscus Haeckel, 1879 Staurodiscus Haeckel, 1879: 145 , type species Staurodiscus tetrastaurus Haeckel, 1879 ( Kramp, 1961: 147 ) . Staurodiscalma Haeckel, 1879: 145 , type species Staurodiscus tetrastaurus Haeckel, 1879 by monotypy. Staurodiscema Haeckel, 1879: 146 , type species Staurodiscus heterosceles Haeckel, 1879 by monotypy. Toxorchis Haeckel, 1879: 157 , type species Toxorchis arcuatus Haeckel, 1879 by monotypy. Staurodiscoides Uchida, 1927b: 165 , type species Staurodiscoides gotoi Uchida, 1927 by monotypy. Diagnosis: Medusa with 4 or more main primary radial canals, some or all branching one or more times, primary canal and some or all of the branches reaching circular canal; gonads on primary radial canals and branches; numerous tentacles and cordyli; with or without cirri; with or without ocelli. Hydroid epizootic, Hebella -like; hydrothecae almost conical when growing on upper part of the host, cylindrical when growing on lower part of same host; asymmetrical to symmetrical; with everted margin, sharply or slightly oblique, with short to long, wrinkled or annulated pedicels; with membranous diaphragm (sometimes absent) and annular thickening; gonophores as free medusae; gonotheca as big or slightly bigger than hydrotheca, with four opercular flaps, on short pedicel, slightly undulated walls, truncated distally, tapering at base, containing up to three medusae ( Bouillon et al ., 2006 ). Remarks: See Kramp (1962) and Bouillon (1984b) for emended diagnosis and synopsis of the species. For the life cycle see Migotto & Andrade (2000) .