Body small, broad, firm and opaque. Head fairly large. One pair of lateral fins entirely on the tail segment; the fins are completely rayed. Collarette voluminous, extending over the entire trunk segment, from the neck to the anterior part of the lateral fins. Alimentary diverticula absent. Eyes small and oval, with T-shaped pigment spot.
Ovaries long and broad, reaching to the neck region; ova very large. Seminal vesicles consisting of an elongated posterior part close to the tail fin and an anterior knob, touching the lateral fins. Hooks 8-10. Teeth in two rows, 6-10 anterior, 8-18 posterior.
Maximum body length 11 mm; relative tail length 38-45%.
Epipelagic, not below 300 m.
Distribution in the North Sea
Entering the North Sea from the adjacent NE Atlantic waters.
Epipelagic in all temperate and tropical oceans.
[After Pierrot-Bults and Chidgey, 1988]