Broch, 1913
Description
Umbrella smooth and somewhat flattened; exumbrella with a circular, coronal furrow situated about midway between umbrella margin and apex; jelly fairly thick [N.atlantica-adult ]. Umbrella margin with 16 slightly elongated lappets with evenly rounded margins [N.atlantica-subumbrella ]; the eight solid adradial marginal tentacles alternate with four perradial and four interradial marginal sense organs. Marginal sense organ with rhopalium with hood, statocyst and sensory bulb, and large flat wedge-shaped basal cushion with straight exumbrellar carina.
Stomach attached interradially to subumbrellar summit over four flattened triangular gastric septa; eight phacelli, one along each side of each triangular septal plate, each with 20+ simple gastric filaments, more than 160 in total. Manubrium slightly folded, not extending beyond umbrella margin. The eight adradial gonads are elongated distally nearly to distal margin of coronal muscle.
Size
Umbrella up to 35 mm in diameter.
Colour
Umbrella uniformly coloured chocolate red; stomach walls are especially densely coloured; underside of umbrella especially dark [N.atlantica-habitus ].
Ecology and depth range
Deep-water oceanic.
Distribution in the North Sea
This deep-water species is unlikely to occur in the northern North Sea.
World distribution
North Atlantic Ocean; has not been recorded farther north than 48°29’ N. The South Atlantic N. rubra may be conspecific.
[After Russell, 1970a; Russell, 1976]