Sabellida is a suborder of annelid

Annelid

The annelids , formally called Annelida , are a large phylum of segmented worms, with over 17,000 modern species including ragworms, earthworms and leeches...

 worms in the class Polychaeta. They are filter feeders with no buccal organ. The prostomium

Prostomium

Prostomium is the first body segment in annelid worms. It is in front of the mouth, being usually a small shelf- or lip-like extension over the dorsal side of the mouth. It sometimes bears antennae and eyes. It often functions like a kind of overlip when the animal is feeding...

 is fused with the peristomium and bears a ring of feathery feeding tentacles. They live in parchment-like tubes made of particles from their environment such as sand and shell fragments cemented together with mucus.

Members of the suborder include the feather duster worms (Sabellidae) and serpulid worms

Serpulidae

Serpulidae is a family of sessile, tube-building annelid worms in the class Polychaeta. The members of this family differ from the sabellid tube worms in that they have a specialized operculum that blocks the entrance of their tubes when they withdraw into the tubes. In addition, serpulids secrete...

 (Serpulidae). Among the species are the giant feather duster worm (Eudistylia polymorpha

Eudistylia polymorpha

Eudistylia polymorpha, the giant feather duster worm, is a species of marine polychaete worm belonging to the family Sabellidae. It receives its common name from the crown of tentacles that are extended when the animal is underwater.-Description:...

), the peacock worm (Sabella pavonina), the European fan worm (Sabella spallanzanii) and the Christmas tree worm (Spirobranchus giganteus

Spirobranchus giganteus

Spirobranchus giganteus, commonly known as Christmas tree worms, are small, tube-building polychaete worms belonging to the family Serpulidae.-Anatomy and morphology:...

).