(Forbes, 1846)
Description
Umbrella bell-shaped, higher than wide; jelly thick [Dipurena halterata ]; velum moderately broad. Four radial canals and ring canal narrow; radial canals with linear swellings. Apical chamber distinct, globular.
Manubrium cylindrical, with bulbous mass at its oral end; when fully stretched, extended 2-3 times length of umbrella; mouth circular, simple.
Gonads discontinuous, with two or more segments completely surrounding distal half of manubrium.
Four perradial marginal tentacles with 3-6 terminal nematocyst rings and large terminal knob. Marginal tentacle bulbs moderately large, with a large ocellus each.
Young medusa: D.halterata-newly and D.halterata-yuong-habitus .
Size
Umbrella up to 8 mm high and 6 mm wide.
Colour
Tentacle bulbs tinged bright green above and orange, red, reddish brown or brown below [D.halterata-habitus ]; tentacular terminal knobs red or brownish; ocelli black or deep crimson; apical chamber reddish or green.
Ecology and depth range
Neritic. Never encountered in large numbers, medusae can be caught in the months April to November.
Distribution in the North Sea
Northern and southern North Sea, English Channel.
World distribution
North Atlantic Ocean including Mediterranean Sea; eastern South Atlantic and Indo-Pacific Oceans.
[After Russell, 1950b; Russell, 1953a; Kramp, 1959; Bouillon, 1999]