(Haeckel, 1877)
Description
Umbrella bell-shaped, higher than wide; jelly thick [Dipurena ophiogaster ]; velum moderately broad. Four radial canals and ring canal narrow. Apical chamber distinct, globular.
Manubrium cylindrical, with bulbous mass at its oral end; when fully extended several times longer than umbrella; mouth circular, simple [D.ophiogaster-habitus ].
Gonads discontinuous, with 2-6 segments completely surrounding manubrium leaving upper part free [D.ophiogaster-medusae ].
Four perradial marginal tentacles beset with scattered nematocyst clusters and small terminal cluster. Marginal tentacle bulbs moderately large, with one ocellus each.
Young medusa: D.ophiogaster-young-habitus .
Size
Umbrella 5 mm high.
Colour
Apical chamber and tentacle bulbs yellowish brown or reddish yellow; manubrium and gonads sometimes rose-coloured [D.ophiogaster-habitus ]; marginal tentacles pale brownish when contracted; ocelli black.
Ecology
Fairly common between May and September in south-western British waters.
Distribution in the North Sea
May be absent from the North Sea; W English Channel.
World distribution
Northwest European waters, Mediterranean; Indo-Pacific Oceans.
[After Russell, 1950b; Russell, 1953a; Kramp, 1959]