Genus Protula Risso, 1826

Type-species: Protula rudolphi Risso, 1826, junior synonym of Serpula tubularia Montagu, 1803 Number of species: 23

Diagnosis. Tube white, (semi-) circular in cross-section, collar-like rings and keels absent. Operculum and pseudo-operculum absent. Radioles arranged in two semi-circles to a spire of up to 6 whorls, up to 320 per lobe. Interradiolar membrane present. Branchial eyes present or absent. Stylodes absent. Mouth palps present. 7 thoracic chaetigerous segments. Collar trilobed, tonguelets absent. Thoracic membrane large, forming ventral apron across anterior abdominal segments. Thoracic triangular depression absent. Collar chaetae limbate. Apomatus chaetae present. Abdominal neurochaetae sickle-shaped with serrated blade. Uncini rasp-shaped throughout with rows of teeth and elongated terminal pegs. Posterior capillary chaetae present.