Adyte pellucida (Ehlers, 1864) accepted as Subadyte pellucida (Ehlers, 1864) (source of synonymy)
Amaeana trilobata (Sars, 1863) (additional source)
Ampharete finmarchica (M. Sars, 1865) (additional source)
Amphicteis gunneri (M. Sars, 1835) (additional source)
Amphitrite cirrata Müller, 1776 (additional source)
Antinoella sarsi (Kinberg in Malmgren, 1866) accepted as Bylgides sarsi (Kinberg in Malmgren, 1866) (additional source)
Aricidea simonae Laubier & Ramos, 1974 represented as Aricidea (Acmira) simonae Laubier & Ramos, 1974 (additional source)
Aricidea wassi Pettibone, 1965 represented as Aricidea (Aricidea) wassi Pettibone, 1965 (additional source)
Chrysopetalum fragile Ehlers, 1864 accepted as Chrysopetalum debile (Grube, 1855) (source of synonymy)
Cirratulus caudatus Levinsen, 1893 (additional source)
Cirrophorus furcatus (Hartman, 1957) (additional source)
Demonax cambrensis Knight-Jones & Walker, 1985 accepted as Parasabella cambrensis (Knight-Jones & Walker, 1985) (additional source)
Dipolydora caulleryi (Mesnil, 1897) (additional source)
Dipolydora coeca (Örsted, 1843) (additional source)
Dipolydora giardi (Mesnil, 1893) (additional source)
Dipolydora quadrilobata (Jacobi, 1883) (additional source)
Dipolydora socialis (Schmarda, 1861) (additional source)
Ditrupa arietina (O. F. Müller, 1776) (additional source)
Euclymene droebachiensis (Sars, 1872) (additional source)
Eunereis elitoralis (Eliason, 1962) accepted as Nereis elitoralis Eliason, 1962 (additional source)
Eunoe nodosa (M. Sars, 1861) (additional source)
Galathowenia oculata (Zachs, 1923) (basis of record)
Harmothoe (Antinoella) sarsi (Kinberg in Malmgren, 1866) accepted as Bylgides sarsi (Kinberg in Malmgren, 1866) (source of synonymy)
Harmothoe nodosa (M. Sars, 1861) accepted as Eunoe nodosa (M. Sars, 1861) (basis of record)
Heteroclymene Arwidsson, 1906 (additional source)
Heteroclymene robusta Arwidsson, 1906 (additional source)
Leitoscoloplos mammosus Mackie, 1987 (additional source)
Lumbrineris fragilis (O.F. Müller, 1776) accepted as Scoletoma fragilis (O.F. Müller, 1776) (source of synonymy)
Lumbrineris tetraura (Schmarda, 1861) accepted as Scoletoma tetraura (Schmarda, 1861) (source of synonymy)
Magelona rosea Moore, 1907 (additional source)
Malacoceros ciliatus (Keferstein, 1862) accepted as Malacoceros tetracerus (Schmarda, 1861) (additional source)
Microspio atlantica (Langerhans, 1880) (additional source)
Minuspio cirrifera (Wirén, 1883) accepted as Prionospio cirrifera Wirén, 1883 (source of synonymy)
Myriochele oculata Zachs, 1923 accepted as Galathowenia oculata (Zachs, 1923) (additional source)
Nematonereis unicornis Schmarda, 1861 accepted as Nematonereis unicornis (Grube, 1840) accepted as Lysidice unicornis (Grube, 1840) (additional source)
Odontosyllis gibba Claparède, 1863 (additional source)
Ophelia borealis Quatrefages, 1866 (additional source)
Ophiodromus flexuosus (Delle Chiaje, 1827) accepted as Oxydromus flexuosus (Delle Chiaje, 1827) (additional source)
Ophiodromus pallidus (Claparède, 1864) accepted as Oxydromus pallidus Claparède, 1864 (additional source)
Ophiura brachiata (Montagu, 1804) accepted as Acrocnida brachiata (Montagu, 1804) (basis of record)
Phyllodoce (Anaitides) groenlandica Örsted, 1842 represented as Phyllodoce groenlandica Örsted, 1842 (additional source)
Phylo norvegicus (M. Sars in G.O. Sars, 1872) accepted as Phylo norvegica (M. Sars in G.O. Sars, 1872) (additional source)
Platynereis dumerilii (Audouin & Milne Edwards, 1833) (additional source)
Podarke pallida (Claparède, 1864) accepted as Oxydromus pallidus Claparède, 1864 (basis of record)
Polydora (Polydora) caulleryi Mesnil, 1897 accepted as Dipolydora caulleryi (Mesnil, 1897) (source of synonymy)
Polydora (Polydora) coeca Örsted, 1843 accepted as Dipolydora coeca (Örsted, 1843) (source of synonymy)
Polydora (Polydora) giardi Mesnil, 1893 accepted as Dipolydora giardi (Mesnil, 1893) (source of synonymy)
Polydora (Polydora) quadrilobata Jacobi, 1883 accepted as Dipolydora quadrilobata (Jacobi, 1883) (source of synonymy)
Polydora ligni Webster, 1879 accepted as Polydora cornuta Bosc, 1802 (source of synonymy)
Prionospio banyulensis Laubier, 1966 accepted as Aurospio banyulensis (Laubier, 1966) (additional source)
Protomystides bidentata (Langerhans, 1880) (source of synonymy)
Rhamphobrachium branchiatum [auctorum] accepted as Rhamphobrachium (Spinigerium) brevibrachiatum (Ehlers, 1874) (source of synonymy)
Rhamphobrachium brevibranchiatum [auctorum] accepted as Rhamphobrachium (Spinigerium) brevibrachiatum (Ehlers, 1874) (additional source)
Sabellides octocirrata (M. Sars, 1835) accepted as Ampharete octocirrata (Sars, 1835) (additional source)
Schistomeringos neglecta (Fauvel, 1923) (additional source)
Scolelepis bonnieri (Mesnil, 1896) (additional source)
Scoletoma fragilis (O.F. Müller, 1776) (additional source)
Scoletoma impatiens (Claparède, 1868) accepted as Scoletoma laurentiana (Grube, 1863) (additional source)
Spio armata (Thulin, 1957) (additional source)
Spio mecznikowianus Claparède, 1869 accepted as Microspio mecznikowiana (Claparède, 1869) (source of synonymy)
Streblospio shrubsolii (Buchanan, 1890) (additional source)
Syllis armillaris (O.F. Müller, 1776) (additional source)
Tomopteris septentrionalis Steenstrup, 1849 (additional source)
Trochochaeta multisetosa (Örsted, 1844) (additional source)
Trypanosyllis coeliaca Claparède, 1868 accepted as Pseudosyllis brevipennis Grube, 1863 (additional source)
Typosyllis (Typosyllis) armillaris (O.F. Müller, 1776) accepted as Syllis armillaris (O.F. Müller, 1776) (source of synonymy)

 Authority

 for Eunoe nodosa (M. Sars, 1861)

Sars, 1861 [details]

 Authority

 for Tomopteris septentrionalis Steenstrup, 1849

Quatrefages, 1849 [details]

 Spelling

 for Phylo norvegicus (M. Sars in G.O. Sars, 1872)

Phylo norvegica (M. Sars, 1872) [details]

 Synonymy

 for Malmgrenia castanea McIntosh, 1876

Malmgrenia castanea is the correct combination, not Malmgreniella castanea [details]

 Synonymy

 for Prionospio malmgreni Claparède, 1869

Prionospio fallax Söderström, 1920 was considered to be a junior synonym of Prionospio malmgreni Claparède, 1869 ... [details]

 Synonymy

 for Sphaerodorum flavum Örsted, 1843

Sphaerodorum flavum could well be a synonym of Sphaerodorum gracilis [details]