Genus Rhopalonema Gegenbaur, 1857

Trachynema Gegenbaur, 1854: 53;

type species Trachynema ciliatum Gegenbaur, 1854 by monotypy.

Rhopalonema Gegenbaur, 1857: 251; type species Rhopalonema velatum Gegenbaur, 1857 by monotypy.

Calyptra Leuckart, 1856: 14; type species Calyptra umbilicata Leuckart, 1856 by monotypy; invalid junior homonym of Calyptra Ochsenheimer 1816 [ Lepidoptera] and others.

Marmanema Haeckel, 1879: 261; type species not designated.

Trachyneme Whiteaves, 1901: 29; spelling error.

Diagnosis: Rhopalonematidae without gastric peduncle; gonads along radial canals; marginal tentacles solid, of two kinds: perradial tentacles long, with large, clubshaped ending; inter- and adradial tentacles short with swollen end. Statocysts enclosed in mesoglea when fully developed.