Body thin and transparent, with a very small head not much broader than the neck. One pair of lateral fins, broad and with fin rays only at the outer edge. Fins situated on both trunk and tail segment. Collarette and alimentary diverticula absent. Small eyes with round pigment spot. Hooks 6-9, strong. Teeth 10-13, triangular and in one, very prominent row, covering the anterior of the head.
Ovaries short, broad, with large ova. Seminal vesicles elongate, situated between lateral and tail fins.
Maximum body length 16 mm, relative tail length 30-40%.
Distribution in the North Sea
Likely to be absent from the North Sea. The species is found near the northern entrance of the North Sea (S. Hay, pers. com.).
Epipelagic, oceanic species.
Cosmopolitan species of warm and temperate regions.
[After Pierrot-Bults and Chidgey, 1988]