(Audouin & Milne-Edwards, 1834)
Body narrow, tapering posteriorly, dorsal surface convex.
Prostomium with a pair of antennae without cirrophores, a pair of biarticulate palps of approximately the same length as the antennae; 2 pairs of eyes in a trapezoid arrangement.
Dorsal tentacular cirri longer than ventral ones, second dorsal tentacular cirrus reaching back to chaetiger 16.
Pharynx with a pair of denticulate jaws; oral and maxillary rings with paragnaths in the form of lines of finely serrated or pectinate bars, absent from groups I, II and V; group III variable, sometimes present as one short line, or as several lines in rows, or sometimes absent; group IV several rows, some consisting of one long line, others of 2 or more short lines; group VI 2 or 3 rows of lines; group Vll-VIII 3-5 short lines arranged around the pharynx with gaps between them (P. dumerilli-proboscis).
Parapodia of the first 2 chaetigers uniramous with 3 lobes.
Remaining parapodia all biramous, with 4 lobes. Parapodia of chaetigers 5-9 with lobes reduced to low mounds, those of chaetigers 3 and 4 and posterior to 9 with longer more pointed lobes. Parapodia of chaetigers 5-9 have 2 notopodial and ventral neuropodial lobes as low rounded structures, neuropodial acicular lobe short and tapering, without a prominent postchaetal lobe. Parapodia of mid-body chaetigers with tapering notopodial lobes and ventral neuropodial lobe, and a shorter neuropodial acicular lobe; notopodial acicular lobe bilobed, an accessory supra-acicular lobe being present, and neuropodial acicular lobe with a prominent postchaetal lobe. Posterior parapodia essentially similar except that notopodial acicular lobe loses its supra-acicular lobe. Dorsal cirri always longer than parapodial lobes, ventral cirri always shorter (P. dumerilli-parapodium). Notopodial chaetae homogomph spinigers, with single homogomph falcigers present in posterior chaetigers. Neuropodial chaetae homogomph spinigers and heterogomph falcigers above and heterogomph spinigers and falcigers below the acicula (P. dumerilli-chaetae).
Up to 90 mm for 100 chaetigers.
Very variable: yellowish, greenish, pink or reddish, with greenish, whitish, reddish or violet spots.
Body divided into 2 regions, an anterior region of 27 chaetigers in males and 24-25 in females, followed by chaetigers with modified parapodia. The dorsal cirri of the first 7 chaetigers in males and the first 5 in females are modified, as are the ventral cirri of the first 4 chaetigers in males only. Metamorphosed parapodia from the posterior part of the body develop accessory flaps at the base of the dorsal cirrus, below the notopodial acicular lobe, on the posterior surface of the neuropodial acicular lobe and at the base of the ventral cirrus. The accessory flaps are better developed in males than in females. In males, crenulations develop along the lower edge of the dorsal cirri, and a pygidial rosette is found. In both sexes, the ordinary chaetae are replaced by paddle chaetae in the modified parapodia.
In the littoral zone from (ELWS) into the sublittoral zone, living in mucous tubes attached to algae etc.
North Sea, North Atlantic from North America to Brazil, Mediterranean, Persian Gulf, Red Sea, Indian Ocean, Pacific, West and South Africa.