De Silva & Knight-Jones, 1962
Description:
Body twisted left, with 3 thoracic chaetigers.
Opercular plate flat (concave in young specimens) or domed, talon bilobed but conical in side view. 3-5 pairs of radioli. Tips of radioli similar in length to adjacent side-branches.
Collar slightly asymmetrical but without obvious flap.
Two last thoracic segments with neuropodia only. Body with a long achaetigerous part between the thorax and abdomen.
Collar chaetae with toothed fin and finely toothed blade (no cross-striations). 2nd and 3rd notopodia with slender, nearly smooth, capillaries; 3rd notopodium with additional Apomatus-chaetae. Abdominal neuropodial chaetae strongly geniculate, with the terminal part coarsely toothed. Uncini with many rows with teeth (S. corallinae-detail).
Size:
Up to 3.5 mm long for 19-28 chaetigers.
Tube:
Tube sinistral, about 1 mm coil diameter, smooth and with the last whorl partially above the previous ones (owing to narrow substratum), walls porcellaneous.
Colour:
Orange coloured.
Habitat:
Normally on Corallina officinalis , occasionally on Chondrus , in rock pools and shallow water.
Distribution:
Irish Sea, English Channel, northern North Sea, Kattegat, Öresund, probably also further distributed in the North Sea and to the east but often mistaken for Spirorbis spirorbis .