Spionida unique characters : Polychaeta with a pair of peristomial grooved feeding palps, with nuchal organs forming posterior projections.
Spionida extended diagnosis: Head blunt or conical and head appendages usually one pair of long food-gathering palps. Eyespots and a short median sensory 'antenna' lobe can be present. Pharynx unarmed, sac-like and at least partly eversible. Parapodial lobes usually well developed and lamella-like. Notochaetae and neurochaetae consist of simple capillaries, hooks, and spines.
Spionida remarks: Families Apistobranchidae, Longosomatidae, Magelonidae, Poecilochaetidae, Spionidae, Trochochaetidae, Uncispionidae, and perhaps Chaetopteridae.
Unique character summary modified after Rouse, G.W.; Pleijel, F. (2001). Polychaetes. Oxford University Press, Oxford. 354 p.
Last modified by G. Read, 21/07/2003 (dd/mm/yy)