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 Merga Hartlaub, 1914 Merga Hartlaub, 1914: 249 ; type species Pandea violacea Agassiz & Mayer, 1899 by original designation. Tiarula Hartlaub, 1914: 253 ; type species Tiara tergestina Neppi & Stiasny, 1912 by original designation. Mergintha Hartlaub, 1914: 250 ; type species Mergintha lobianci Hartlaub, 1914 by monotypy. Janiopsis Bouillon, 1980: 328 ; type species Janiopsis costata Bouillon, 1980 by monotypy; invalid junior homonym of Janiopsis Rovereto, 1899 [ Gastropoda , Buccinidae ]. Diagnosis: Pandeid medusae with smooth or granulate adradial or interradial gonads, with mesenteries, stomach with cross-shaped base, manubrium not twisted, with simple or faintly crenulated oral lips; four, eight, or more tentacles, with or without rudimentary bulbs or tentacle-stumps, with or without ocelli. Hydroids, where known, colonial, arising from tubular, ramified hydrorhiza, cauli slightly branched or not, with or without pseudohydrotheca, when present not enveloping tentacles, one whorl of filiform tentacles. Medusa buds arise from stems or stolons.