Adult. Body short, gelatinous; mantle opening wide, the funnel is embedded in gelatinous tissue. Mantle locking- apparatus distinct and well developed. The funnel organ is W-shaped. The web is deep between all arms. The entire right arm III is hectocotylised, develops in pouch in fron of the eye, and is detachable. Suckers uniserial proximally, biserial distal to the edge of the web. The radula is heterodont. Eyes large, diameter about 40% of mantle length. Shell vestige absent.
Young. Body short, stubby, gelatinous; uniformly pigmented with small chromatophores. Ratio mantle to arm about 1:1. Eyes large and hemispherical. Sucker arrangement and web as in adults.
Unknown; maximum reported total length 200 cm.
Distribution in the North Sea
Several rare records from the northern North Sea and Skagerrak.
Cosmopolitan in tropical and subtropical waters.
[After Hochberg et al., in Sweeney et al., 1992 — as Alloposus mollis Verrill, 1880]