Ellis and Solander, 1786
Valves smooth, transparent and pale blue (especially in living animals), with large gaps between them. Scutum triangular to quadrangular; carinal margin short and not sharply marked off from tergal margin. Internal tooth on both scuta variable in size. Tergum flat, triangular, occludent margin slightly arched or nearly straight. Carina variable in shape, typically broad part above umbo, apex pointed, valve bent angularly at the umbo.
Peduncle yellowish, light bluish or purplish brown.
Mouthparts: Labrum with several small teeth on inner margin. Palpus conical with setae in the inner side. Mandible variable, with five or sometimes four teeth and pectinate lower corner, sometimes with small rudimentary teeth. Maxilla I with the typical Lepas edge, usually with (two) three (four) steps.
Cirri I with rami of about equal length. Caudal appendages short, single jointed and rounded. Five (sometimes four) filamentary appendages on each side, near basis of cirrus I.
Hermaphrodite; penis very setose and transversely annulated.
Capitulum length up to 40 mm; peduncle narrow and shorter than capitulum.
Pelagic, attached to floating algae when young; also attached to small floating objects and then secreting a yellowish ball on which many specimens are congregated (for example pelagic molluscs as Spirula — not in the North Sea — Janthina, flotsam, etc.).
Distribution in the North Sea
Northern North Sea, rare, entering from the Faeroe Channel; S Norway, Skagerrak; even reported from the W Baltic Sea.
Almost cosmopolitan in tropical and subtropical waters, euryhaline and stenothermal, preferring rather high temperatures.
[After Nilsson-Cantell, 1978]