Claparède & Mecznikow, 1869
Description:
Body small.
Prostomium and segments each with a ring of cilia. Prostomium broadly rounded, with two eyes at posterior margin. Two small ovoid antennae dorsally and two small palps of same shape ventrally. Two anterior apodous segments of same length as following chaetigers (O. puerilis-detail).
Parapodium with two conical lobes, with two aciculae. Dorsal and ventral cirri short, bluntly conical. Chaetae of two kinds: 1) 3-4 simple blunt, finely toothed hooks; 2) six compound chaetae with finely toothed hooked blades. Posterior parapodia with 1-2 subacicular simple chaetae (O. puerilis-parapodium). Pygidium short, with two small slender and cylindrical cirri with a minute papilla between them.
Mandibles X-shaped, with finely toothed V-shaped anterior margins. Maxillary carriers fused to each other and to hooked smooth basal maxillae (missing in juveniles); 6-7 pairs of coarsely to finely toothed maxillae (O. puerilis-jaw plates).
Size:
Up to 12 mm; about 30 chaetigers.
Colour:
White or colourless, transparent.
Habitat:
Found on coarse sand and gravel, among plants, tunicates, hydroids, and in mollusc beds. Occurs in intertidal and in shallow subtidal zones.
Distribution:
North Atlantic between White Sea and English Channel, North Sea to western Baltic.