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(Forbes, 1848)

Description
Umbrella bell-shaped, higher than wide; jelly moderately thick [Dipurena gemmifera]; velum narrow. Four radial canals and ring canal very narrow. Sometimes apical canal present, always with globular or conical apical chamber.
Manubrium cylindrical, with bulbous mass at its oral end; when fully extended 3 or more times longer than umbrella; mouth circular, simple, beset with nematocysts.
Asexual budding from manubrium just apical of gonads [D.gemnifera-medusa]. Gonads continuous, completely surrounding bulbous distal section of manubrium.
Four marginal tentacles short, perradial, nematocysts in scattered clusters and on large terminal knob. Single ocellus on each moderately sized marginal tentacle bulb.

Size
Umbrella 5 mm high.

Colour
[D.gemnifera-habitus ] Mouth, apical chamber and marginal tentacle bulbs pale orange-red or straw; terminal knob of marginal tentacles faint orange-red; ocelli black.

Ecology
In south-western British waters medusae are present from May to September, peak abundance usually in August and September.

Depth range

Distribution in the North Sea
All North Sea coasts, as far north as Bergen, Norway.

World distribution
Northwestern Europe and Mediterranean.

[After Russell, 1950b; Russell, 1953a; Kramp, 1959]

Dipurena gemmifera