(A. Agassiz, 1862)
Description
Umbrella with large globular apical projection [Catablema vesicarium ]. The four radial canals broad, with distinctly denticulated edges; interradial centripetal canals absent.
Manubrium large, with broad base, with four short mesenteries. Mouth with four large, crenulated lips.
Gonads on manubrium wall, broadly separated perradially, with more or less vertical irregular folds issuing from the perradial sides surrounding a reticulate area, with isolated interradial pits. With 30-40 marginal tentacles, and equal number of rudimentary tentacles. Tentacular bulbs with abaxial ocelli.
Size
Umbrella up to 25 mm wide and 30 mm high (including apical projection).
Distribution in the North Sea
Skagerrak (intruded from the Arctic)
World distribution
Mainly in arctic waters of Atlantic and Pacific Oceans.
Remark
Polyp not known with certainty.
[After Russell, 1955; Kramp, 1959]