Body clearly divided into 2 regions. Prostomium no more than a simple fold. The numerous buccal tentacles cannot be fully retracted into the mouth. Up to 3 pairs of branchae may be present on anterior segments; these may be simple or branched. Thoracic parapodia are biramous with dorsal winged capillaries and ventral uncini. The abdominal parapodia are uniramous and have uncini only.