Sabellidae

Sabellidae, or feather duster worms, are a family of marine polychaete tube worms characterized by protruding feathery branchiae. Sabellids build tubes out of a tough, parchment-like exudate, strengthened with sand and bits of shell. Unlike the other sabellids, the genus Glomerula secretes a tube of calcium carbonate instead. Sabellidae can be found in subtidal habitats around the world. Their oldest fossils are known from the Early Jurassic. Feather-duster worms have a crown of feeding appendages or radioles in two fan-shaped clusters projecting from their tubes when under water. Each radiole has paired side branches making a two-edged comb for filter feeding. Most species have a narrow collar below the head. The body segments are smooth and lack parapodia. The usually eight thoracic segments bear capillaries dorsally and hooked chaetae (bristles) ventrally.