(Péron and Lesueur, 1809)
Description
Umbrella hemispherical; jelly in upper part moderately thick, thin at sides [Eirene viridula ]. Velum narrow, ca 1/10 bell radius.
Stomach short, situated on elongate conical gastric peduncle which reaches beyond umbrella margin; with four basal projections at entrances to radial canals; mouth having four long lips with crenulate margins [E.viridula-female-habitus ].
The four radial canals and ring canal narrow. With excretory pores on large papillae projecting into subumbrellar cavity and leading from ring canal opposite base of each marginal tentacle.
Gonads on radial canals limited to subumbrellar disc, not extending onto gastric peduncle [E.viridula-female-habitus ]; extending from near base of peduncle almost to ring canal; straight or slightly sinuous, without median furrow.
Up to 70+ short marginal tentacles of rather unequal lengths, with conical bases. Lateral and marginal cirri absent. Up to 50+ closed marginal vesicles each with 1-4 concretions.
Young specimen E.viridula-young-habitus
Size
Diameter of umbrella usually up to ca 30 mm, occasionally larger.
Colour
Colourless except for greenish tinge on stomach.
Ecology
Off Plymouth recorded July-December, most commonly September-October; and 'in more northerly waters in late summer and autumn' (Russell, 1953a).
Distribution in the North Sea
Northern North Sea, Skagerrak, recorded off E Scotland and Jutland.
World distribution
Medusae recorded in Europe from Jutland south along the NW coast of the European mainland to the N coast of France, and further south sporadically to the Bight of Central W Africa; common in Mediterranean Sea; also reported from Djibouti in Indian Ocean (Kramp, 1961), Gulf of Kuwait (Michel et al., 1986), near Amazon estuary (Alvariño, 1968) and Bismarck Sea, Papua New Guinea (Bouillon, 1984b).
[After Cornelius, 1995a]