In the adult state, this animal reaches a length of 20 cM. It is said to emit light by phosphorescence.

The species depicted lives in the Mediterranean Sea at 1 or 2 fathoms. The ovoid anterior section of the elongated, cylindrical, slimy body, the glans , is separated from the subsequent collar by a deep constriction, in which the mouth opening is located. The glans, whose large internal cavity can be filled and emptied with water through two openings, changes its shape and size; it serves, except as a suture when crawling, as a drill when digging passages in the sea bed, in which the body is usually hidden up to the mouth. The alimentary canal, in which, in addition to food, water is also absorbed, is in communion with two longitudinal series of gill pouches , which are located in the anterior or gill part of the trunk on the back. The water, which has been used for breathing, flows out through a series of about 20 fine slits on the ventral side. The widest part of the alimentary canal is in the stomach part of the trunk; it is always filled with sand, the organic components of which serve the animal as food. The tail is grooved annularly; through the terminal vent opening, the sand is ejected, which forms piles next to the opening of the corridor.