Lesson, 1836
Description
Umbrella usually bell-shaped [Bougainvillia macloviana ]; with quadrangular margin and four deep interradial longitudinal furrows; jelly fairly thick; velum moderately broad. The four radial canals and ring canal fairly narrow.
Gastric peduncle well developed, cone-shaped; manubrium short, with four narrow perradial lobes extending along peduncle. Mouth simple, circular with four short perradial lips and four perradial oral tentacles inserted above mouth opening, dichotomously branched 5-7 times and armed with nematocyst clusters [B.macloviana-oral tentacles ].
Gonads slightly folded, extending along perradial lobes of manubrium upwards on gastric peduncle [B.macloviana-medusa ].
Four radially placed large marginal tentacular bulbs each with a cluster of 35-65 solid marginal tentacles in a double row; tentacles of each cluster all similar. Marginal bulbs V-shaped, about half as wide as interradial space; with yellow, red or brownish-black adaxial ocelli.
Size
Umbrella 8-15 mm high.
Colour
Manubrium, gonads, and marginal bulbs bright red, reddish brown or orange.
Ecology and depth range
Meropelagic; neritic. Recorded in the south-eastern North Sea in April-June.
Distribution in the North Sea
Southern North Sea.
World distribution
North Atlantic Ocean including Mediterranean Sea; E and W South Atlantic and Indo-Pacific Oceans; circum-Antarctic.
Remark
Hydroid probably introduced on ships coming from Antarctic waters.
[After Russell, 1953a; Kramp, 1959; Bouillon, 1999]