Sabellida unique characters : Polychaetes with peristomium fused to prostomium, usually with numerous feeding tentacles on head, usually with chaetal inversion in the posterior region.
Sabellida extended diagnosis: Sabellidae and Serpulidae have head appendages which are very numerous semi-rigid radioles or flexible feeding tentacles, arranged in two groups, or more or less as one fan or funnel. The pharynx is not eversible. Short food-handling palps and several eyespots may be present. An operculum may be present. Parapodia usually without lobes, with notochaetal capillaries and usually neurochaetal hooks in the anterior region, reversed in orientation in the posterior region. Sabellariidae also have most of these characters, including chaetal inversion. The head in Oweniidae is blunt and fused to anterior segments. Head appendages may be present or absent. Oweniid notosetae are capillaries and neurosetae are minute hooks in dense fields. Sabellida is also proposed as the group into which the Pogonophora should be placed.
Sabellida remarks: Sabellidae, Serpulidae (includes Spirorbidae), Sabellariidae, Siboglinidae (= pogonophorans), and doubtfully Oweniidae.
Last modified by G. Read, 21/07/2003 (dd/mm/yy)