Body short or long, prostomium without appendages, palps absent. Pharynx a ventral muscular pad. Some anterior segments may be fused and asetigerous; some segments with median dorsal cirri; paired lateral branchiae present in some juveniles. Setae in double fascicles; parapodial lobes absent. This small family of tiny polychaetes recently has been reorganized and redefined by Hartmann-Schroder.
Fauchald, K. 1977. The polychaete worms, definitions and keys to the orders, families and genera. Natural History Museum of Los Angeles County: Los Angeles, CA (USA) Science Series 28:1-188