Pierantoni, 1908
Description:
Tentacles comparatively long, about 1/5 or 1/6 as long as the body length. Two red-brown eyes at bases of tentacles, occasionally lacking. Two relatively large so-called statocysts between and slightly anterior to eyes. Nuchal organs dorsolateral. Head with 5-6 lateral transverse ciliary rows as well as numerous ciliary tufts and several sensory cilia on the head. Each segment with one dorsally incomplete ring of ciliary tufts; short and long sensory cilia abundant. Epidermis with different types of glands, especially on the ventral side. Two pygidial lobes of variable shape, ending in a lateral tip. Salivary glands extending to segments 4 or 5 only.
Lateral organs forming continuous grooves from segment 7 to 15. Four pairs of spermioducts in segments 11-14. Oviducts lacking. Fertile region beginning in segments 11 or 12, occasionally in segment 10.
Size:
Up to 3.5-5.0 mm for 30-35 segments.
Colour:
Transparent, whitish.
Habitat:
Mostly subtidal sediments of generally coarse sand; sometimes up to the low water line.
Distribution:
North Sea (Helgoland), English Channel, Skagerrak (Swedish west coast, Gullmarfjord), Mediterranean.