Genus Liriope Lesson, 1843 Liriope Lesson, 1843: 331; type species Liriope cerasiformis Lesson, 1843 (Haeckel, 1979: 288). Xanthea Lesson, 1843: 333; type species Xanthea agaricina Lesson, 1843 by monotypy. Leuckartia L. Agassiz, 1862: 364; type species Leuckartia proboscidalis L. Agassiz, 1862 by monotypy. Glossocodon Haeckel, 1864b: 460; type species Liriope eurybia Haeckel, 1864 by monotypy. Glossocodon (Glossoconus) Haeckel, 1864b: 461; no type species designated. Liriantha Haeckel, 1879: 286, no type species designated. Liriantha (Lirianthella) Haeckel, 1879: 286; no type species designated. Liriantha (Lirianthissa) Haeckel, 1879: 287; no type species designated. Liriope (Liriopella) Haeckel, 1879: 289; no type species designated. Liriope (Liriopissa) Haeckel, 1879: 290; no type species designated. ? Pentaradiata Zamponi & Gezano, 1989: 34; type species Pentarradiata estuariensis Zamponi & Genzano, 1989 by monotypy. ? Heptarradiata Zamponi & Gezano, 1989: 35; type species Heptarradiata rioplatensis Zamponi & Genzano, 1989 by monotypy. ? Octorradiata Zamponi & Gezano, 1989: 36; type species Octorradiata bonaerensis Zamponi & Genzano, 1989 by monotypy. Diagnosis: Limnomedusae with long gastric peduncle; stomach small, with 4 lips; 4 radial canals, with additional centripetal canals; 4 gonads on radial canals, flattened and leaf-shaped; two kinds of marginal tentacles, solid and hollow; ecto-endodermal statocysts enclosed in mesoglea. No polyp stage, direct developement. Remarks: Rarely, aberrant animals with more than four radial canals and gonads can occur, but the number of oral lips remains rather constantly four (Bouillon et al., 2006).

Published as part of Schuchert, Peter & Collins, Richard, 2021, Hydromedusae observed during night dives in the Gulf Stream, pp. 237-356 in Revue suisse de Zoologie 128 (2) on pages 337-338, DOI: 10.35929/RSZ.0049, http://zenodo.org/record/5639938