Body elongate and worm-like, usually not exceeding 10 mm in length; transparent without pigment.
There are 10 tentacles, which are simple (without digits).
This species lacks tube-feet.
The skin contains calcareous deposits which consist of anchors and anchor plates. The anchor is narrower than the anchor plate. The anchor plates have only 3 holes in the articular end, the middle one is very narrow and slit-like. There are also plates with 4 holes (L. minuta spicules).
It lives on muddy or coarse gravel bottoms, in areas of strong current, at depths of about 20 m.
This species was described from Helgoland in the North Sea. It is still mainly known from this locality. However, the species is probably more widely distributed but under-recorded because of the difficulty of sorting it out from coarse substratum.