Body anteriorly conical and pointed, posteriorly slightly flattened.
Prostomium composed of 8-10 rings, with two small eyes and palps and antennae forming a cross at the tip.
Anterior 36-37 parapodia uniramous with conical prechaetal lamellae and triangular dorsal and ventral cirri. Posterior parapodia biramous with a small, rounded notopodium. Dorsal and ventral cirri triangular. Notopodia with two or three thick chaetae only. Neuropodial chaetae compound with long, denticulate blades.
Pharynx with 18 terminal papillae. Macrognaths big with 2-3 bigger and 2-3 smaller teeth. 20-29 micrognaths in a full circle (G. nordmanni-detail).
Up to 60 mm long for 150 segments.
Living animal pink to yellowish.
In mud, but also in mixtures of sand and mud or stones and mud/shells. Sublittoral to depths of 500 m.
Whole North Sea, Skagerrak, Kattegat, English Channel, Arctic, North Pacific, North Atlantic and Mediterranean.