(Chamisso and Eysenhardt, 1821)
Description
Umbrella almost hemispherical [L.tetraphylla-habitus ]; jelly thick, especially in apical region; marginal nematocyst ring present, with four perradial and four interradial short nematocyst tracks on exumbrella; velum well-developed. Usually with four straight radial canals; with 1-3 (or more) short blind centripetal canals in each quadrant; ring canal broad.
Manubrium on long gastric peduncle of 1-3 times umbrella height [L.tetraphylla-habitus ]; mouth with four simple or slightly crenulated lips. Subumbrellar portion of radial canals with four, flattened and leaf-shaped, gonads which are very variable in shape and size [L.tetraphylla-medusa ].
Four long hollow perradial marginal tentacles with nematocyst rings and four small solid interradial tentacles with adaxial nematocyst clusters. Eight ecto-endodermal statocysts enclosed in mesogloea.
Size
Umbrella 10-30 mm wide.
Colour
Manubrium, gonads and marginal tentacles rose-red or green.
Ecology and depth range
Holopelagic, epipelagic; species of warm and tropical oceanic waters where it floats in great shoals usually near the surface. Medusae are present throughout the year, its local occurrence determined by hydrographic conditions.
Distribution in the North Sea
May be carried into the English Channel by the flow of Atlantic water.
World distribution
North Atlantic Ocean, Mediterranean Sea; E and W South Atlantic and Indo-Pacific Oceans.
Remark
Polyp stage absent.
[After Russell, 1953a; Kramp, 1959; Bouillon, 1999]