Body short and thick, U-shaped. Epidermis densely papillated with round papillae, coated with fine sand.
Prostomium and peristomium without eyes, with two grooved palps and 6-8 filamentous gills in two groups, retractile.
Notopodial chaetae very small, 0-4 per segment.
Neuropodial chaetae of the first chaetiger capillary, the others 2-9 distally bent spines (B. inhabilis-detail).
Up to 60 mm for 26 segments.
Living animal orange. In alcohol grey.
On sand, mud, gravel, mixed bottoms, between stones; eulittoral to 3000 m.
Arctic, North Pacific, North Atlantic, northern North Sea to Öresund.