Common polychaetes. Cylindrical shape of body: anterior part with capillary chaeta and posterior part with long-handled hooks.

      Genus: Capitella de Blainville,1828
  Species: Capitella capitata (Fabricius, 1780)

      Genus: Heteromastus Eisig,1887
  Species: Heteromastus filiformis (Claparéde, 1864)

      Genus: Notomastus M. Sars,1850
  Species: Notomastus latericeus Sars, 1851

Mainly in mixed sand and muds of deeper sea. Small (up to 20mm) with characteristic mid-dorsal branchia.

      Genus: Cossura Webster & Benedict,1887
  Species: Cossura longocirrata Webster & Benedict, 1887
  Species: Cossura pygodactylata Jones,1956

Bamboo-worms. Body of set number of long cyrindrical segments with low rows of hooked chaetae.

      Genus: Axiothella Verrill,1900
  Species: Axiothella catenata (Malmgren, 1865)

      Genus: Chirimia Light,1991
  Species: Chirimia biceps (M. Sars, 1861)

      Genus: Clymenura Verrill,1900
  Species: Clymenura polaris (Théel, 1879)

      Genus: Lumbriclymene M. Sars, in G.O. Sars,1872
  Species: Lumbriclymene minor Arwidsson, 1906

      Genus: Maldane Grube,1860
  Species: Maldane sarsi Malmgren, 1865

      Genus: Nicomache Malmgren,1865
  Species: Nicomache lumbricalis (Fabricius, 1780)

      Genus: Notoproctus Arwidsson,1906
  Species: Notoproctus oculatus Arwidsson, 1906

      Genus: Petaloproctus de Quatrefages,1866
  Species: Petaloproctus borealis Arwidsson,1906
  Species: Petaloproctus tenuis (Théel, 1879)

      Genus: Praxillella Verrill,1881
  Species: Praxillella gracilis (M. Sars, 1861)
  Species: Praxillella praetermissa (Malmgren, 1865)

      Genus: Rhodine Malmgren,1865
  Species: Rhodine gracilior Tauber, 1879

Fixed number of segments (30-60). Different body shape depending on species.

      Genus: Ophelia de Savigny,1822
  Species: Ophelia limacina (Rathke, 1843)

      Genus: Ophelina Örsted,1843
  Species: Ophelina acuminata Örsted, 1843

      Genus: Travisia Johnston,1840
  Species: Travisia forbesii Johnston, 1840

Burrowers. Up to several hundreds segments, with anterior thoracic region and more fragile abdomen.

      Genus: Leitoscoloplos Day,1977
  Species: Leitoscoloplos mammosus Mackie, 1987

      Genus: Naineris de Blainville,1828
  Species: Naineris quadricuspida (Fabricius, 1780)

      Genus: Scoloplos de Blainville,1828
  Species: Scoloplos armiger (Müller, 1776)

In deeper waters, relatively little known. Small (up to 40 mm), with up to 200 segments and fragile body.

      Genus: Aricidea Webster, 1879
  Species: Aricidea (Allia) suecica Eliason, 1920
  Species: Aricidea quadrilobata Webster & Benedict, 1887

      Genus: Cirrophorus Ehlers,1908
  Species: Cirrophorus eliasoni (Mackie, 1991)

      Genus: Paraonella Strelzov, 1973
  Species: Paraonella nordica Strelzov, 1968

      Genus: Levinsenia Mesnil, 1897
  Species: Levinsenia gracilis (Tauber, 1879)

Maggot worms. Up to 60 mm, 30-60 segments. Body short and stout or more elongate, with body tapering from an anterior wide point.

      Genus: Scalibregma Rathke, 1843
  Species: Scalibregma inflatum Rathke, 1843

In intertidal and shallow coarse sediments and muds. Small to moderate size (5-150 mm).

      Genus: Macrochaeta Grube,1850
  Species: Macrochaeta clavicornis (M.Sars, 1835)

Taxonomically problematic group. Body not distinctly regionated, but the anterior and posterior parts are shorter and wider than those in mid body. Most less than 50 mm.

      Genus: Cirratulus de Lamarck,1801
  Species: Cirratulus cirratus (O. F. Müller, 1776)

      Genus: Dodecaceria Örsted,1843
  Species: Dodecaceria concharum Örsted, 1843

      Genus: Tharyx Webster & Benedict, 1887
  Species: Tharyx sp.

      Genus: Aphelochaeta J.A. Blake,1991
  Species: Aphelochaeta marioni (de Saint Joseph, 1894)

      Genus: Chaetozone Malmgren,1867
  Species: Chaetozone christei Chambers, 2000
  Species: Chaetozone setosa Malmgren, 1867
  Species: Chaetozone jubata Chambers & Woodham, 2003

Bristle-cage worms. Papillose body, often coated with thick covering of sediment. Head completely retractable between anterior segments. Not more than 100 segments, body from 5 to 220 mm.

      Genus: Brada Stimpson,1854
  Species: Brada villosa (Rathke, 1843)
  Species: Brada inhabilis (Rathke, 1843)
  Species: Brada rugosa (Hansen, 1882)

      Genus: Flabelligera M. Sars,1829
  Species: Flabelligera affinis M. Sars, 1829

      Genus: Pherusa Oken,1807
  Species: Pherusa plumosa (Müller, 1776)

      Genus: Diplocirrus Haase,1915
  Species: Diplocirrus longisetosus (Marenzeller, 1890)

Ice-cream cone or trumpet worms. Mainly in shallow sediments. In elegant cone-shaped tubes, constracted from sand, small shells or other small particles. From 10 to 250 mm, not more than 20 chaetigerous segments.

      Genus: Pectinaria de Lamarck, 1818
  Species: Pectinaria (Cistenides) hyperborea (Malmgren, 1866)

Tubicolous, with multiple grooved tentacles easily retractable into the mouth. 10-60 mm long. Two distinct regions of the body: thoracic with biramous parapodia and an abdomen with neuropodia only.

      Genus: Amage Malmgren,1866
  Species: Amage auricula Malmgren, 1866

      Genus: Ampharete Malmgren,1866
  Species: Ampharete finmarchica (M. Sars, 1864)
  Species: Ampharete goesi Malmgren, 1866

      Genus: Amphicteis Grube,1850
  Species: Amphicteis gunneri (M. Sars, 1835)

      Genus: Anobothrus Levinsen,1884
  Species: Anobothrus gracilis (Malmgren, 1866)
  Species: Anobothrus laubieri (Desbruyeres, 1978)

      Genus: Glyphanostomum Levinsen,1884
  Species: Glyphanostomum pallescens (Theel, 1879)

      Genus: Lysippe Malmgren,1866
  Species: Lysippe labiata Malmgren, 1866

      Genus: Melinna Malmgren,1866
  Species: Melinna cristata (M. Sars, 1851)
  Species: Melinna elisabethae McIntosh,1922

      Genus: Sabellides H. Milne-Edwards,1838, emend. Malmgren,1866
  Species: Sabellides borealis Sars, 1856

Spagetti worms. Large diversity of forms, from 10 to 300 mm. With multiple grooved tentacles. Two distinct parts of body in addition to head: thoracic region with biramous parapodia and long tapering abdomen with neuropodia only.

      Genus: Amphitrite O.F. Müller,1771
  Species: Amphitrite cirrata (O. F. Müller, 1771)

      Genus: Axionice Malmgren,1866
  Species: Axionice maculata (Dalyell, 1853)

      Genus: Lanassa Malmgren,1866
  Species: Lanassa nordenskioldi Malmgren, 1866

      Genus: Leaena Malmgren,1866
  Species: Leaena ebranchiata (M. Sars, 1865)

      Genus: Neoamphitrite Hessle,1917
  Species: Neoamphitrite affinis (Malmgren, 1866)
  Species: Neoamphitrite groenlandica (Malmgren, 1866)

      Genus: Nicolea Malmgren,1866
  Species: Nicolea zostericola Örsted, 1844

      Genus: Proclea de Saint-Joseph,1894
  Species: Proclea malmgreni (Ssolowiew, 1899)

      Genus: Hauchiella Levinsen,1893
  Species: Hauchiella tribullata (McIntosh, 1869)

      Genus: Thelepus Leuckart,1849
  Species: Thelepus cincinnatus (Fabricius, 1780)

      Genus: Artacama Malmgren,1866
  Species: Artacama proboscidea Malmgren, 1866

      Genus: Laphania Malmgren,1866
  Species: Laphania boecki Malmgren, 1866

      Genus: Polycirrus Grube,1850
  Species: Polycirrus arcticus Sars, 1865

      Genus: Terebellides M. Sars,1835
  Species: Terebellides stroemi Sars, 1835

      Genus: Trichobranchus Malmgren,1866
  Species: Trichobranchus glacialis Malmgren, 1866
  Species: Trichobranchus roseus (Malm, 1874)
  Species: Trichobranchus sikorski Leontovich & Jirkov, sp. nov.

Tubiculous. 10-400 mm, less than 60 segments.

      Genus: Apistobranchus Levinsen,1883
  Species: Apistobranchus tullbergi (Théel, 1879)

Little is known about the group. Easily fragmented in collection.

      Genus: Spiochaetopterus M.Sars, 1853
  Species: Spiochaetopterus typicus M.Sars, 1856

With easily lost pair of elongate grooved palps extending from the head. From several millimeters to several centimeters.

      Genus: Prionospio Malmgren,1867
  Species: Prionospio cirrifera Wiren, 1883

      Genus: Spiophanes Grube,1860
  Species: Spiophanes kroyeri Grube, 1860

      Genus: Dipolydora Verrill,1879
  Species: Dipolydora quadrilobata (Jacobi, 1883)
  Species: Dipolydora coeca (Örsted, 1843)

      Genus: Glyphochaeta Bick, 2005
  Species: Glyphochaeta laudieni Bick, 2005

      Genus: Spio Fabricius, 1785
  Species: Spio armata (Thulin, 1957)

      Genus: Laonice Malmgren, 1867
  Species: Laonice cirrata (M. Sars, 1851)

In distinctive tightly fitting sediments tubes. Body elongate, cylindrical, with 20-30 segments. From 10 – 100 mm, with tubes larger and reaching 200-300 mm.

      Genus: Owenia delle Chiaje, 1841
  Species: Owenia fusiformis delle Chiaje, 1841

      Genus: Galathowenia Kirkegaard,1959
  Species: Galathowenia fragilis (Nilson & Holthe, 1985)
  Species: Galathowenia oculata (Zachs, 1923)

      Genus: Myriochele Malmgren,1867
  Species: Myriochele heeri Malmgren, 1867

Feather-duster worms, with radiolar crown and mucus/parchment/sediment tubes. From 0.85 mm to 450 mm, 11 – hundreds of segments.

      Genus: Chone Kröyer,1856
  Species: Chone fauveli McIntosh,1916
  Species: Chone spp.

      Genus: Fabricia de Blainville,1828
  Species: Fabricia stellaris stellaris (O. F. Müller, 1774)

      Genus: Euchone Malmgren,1866
  Species: Euchone analis (Kröyer, 1856)

      Genus: Laonome Malmgren,1866
  Species: Laonome kroeyeri Malmgren, 1866

Fanworms. With radiolar crown, in calcareous tubes. From 2 to 100 mm.

      Genus: Ditrupa Berkeley,1835
  Species: Ditrupa arietina (O. F. Müller, 1776)

      Genus: Protula Risso,1826
  Species: Protula tubularia (Montagu, 1803)

      Genus: Placostegus Philippi,1844
  Species: Placostegus tridentatus (Fabricius, 1779)

      Genus: Bushiella Knight-Jones,1973
  Species: Bushiella (Jugaria) quadrangularis (Stimpson, 1854)
  Species: Bushiella (Jugaria) similis (Bush, 1905)

      Genus: Metavermilia Bush,1904
  Species: Metavermilia arctica Kupriyanova, 1993

Morphologically uniform, with short body, as long as wide. With characteristic brittle, calcareous chaetae.

      Genus: Euphrosine de Lamarck,1818
  Species: Euphrosine borealis Örsted, 1843

Morphologically heterogeneous group. From few segments and micrometers in length to several centimeters and large number of segments.

      Genus: Parougia Wolf,1986
  Species: Parougia sp.

      Genus: Ophryotrocha Claparède & Mecznikow, 1869
  Species: Ophryotrocha cosmetandra Oug, 1990
  Species: Ophryotrocha cf. scarlatoi Averincev, 1989
  Species: Ophryotrocha spatula Fournier & Conlan, 1994

Medium-sized to large worms, from few centimeters to over half of meter in length and several hundreds of segments. Free living with jaws.

      Genus: Lumbrineris de Blainville, 1828
  Species: Lumbrineris fragilis (O.F.Müller, 1766)
  Species: Lumbrineris mixochaeta Oug, 1998

Anterior part often cylindrical and widest becoming medially and posteriorly more flattened. Most tubiculous.

      Genus: Paradiopatra Ehlers, 1887
  Species: Paradiopatra quadricuspis (M. Sars in G.O. Sars, 1872)

      Genus: Nothria Malmgren,1867
  Species: Nothria conchylega (Sars, 1835)

Scale worms with simple chaetae. Dorso-ventrally flattened. Sea mice within the group.

      Genus: Laetmonice Kinberg, 1855
  Species: Laetmonice filicornis Kinberg, 1855

Small (up to 20 mm, up to 90 segments), short-bodied scale worms. Stiff body.

      Genus: Pholoe Johnston,1839
  Species: Pholoe assimilis Örsted, 1845

Scale worms with simple chaetae. Dorso-ventrally flattened.

      Genus: Harmothoe Kinberg,1855
  Species: Harmothoe imbricata (Linnaeus, 1767)

      Genus: Eunoe Malmgren,1865
  Species: Eunoe oerstedi Malmgren, 1865

      Genus: Gattyana McIntosh, 1897 emend. Pettibone, 1953
  Species: Gattyana cirrhosa (Pallas, 1766)

      Genus: Bylgides Chamberlin, 1919
  Species: Bylgides elegans (Théel, 1879)
  Species: Bylgides groenlandicus (Malmgren, 1867)

      Genus: Enipo Malmgren,1865
  Species: Enipo torelli (Malmgren, 1865)

With golden, flattened notochaetae that cover the dorsum. Small to moderate size, from 1 to 50mm and 10 to over 300 segments. Dorso-ventrally flattened with paleae or more elliptical and resemble.

      Genus: Dysponetus Levinsen, 1879
  Species: Dysponetus pygmaeus Levinsen, 1879

Common in sublittoral, especially in rocky or mixed bottom. Heterogeneous, from few millimeters to several centimeters. Extremely fragile.

      Genus: Nereimyra de Blainville, 1828
  Species: Nereimyra punctata (Müller, 1776)

      Genus: Microphthalmus Mecznikow, 1865
  Species: Microphthalmus sp.

Ragworms. From few millimeters to over meter long, from 15 to several hundreds segments. The most familiar family.

      Genus: Nereis Linnaeus, 1758
  Species: Nereis zonata Malmgren, 1867
  Species: Nereis pelagica Linnaeus, 1758

Large, variable but highly characteristic group.

      Genus: Syllis de Lamarck, 1818
  Species: Syllis cornuta Rathke, 1843

      Genus: Sphaerosyllis Claparède, 1863
  Species: Sphaerosyllis erinaceus Claparède, 1863

      Genus: Myrianida Milne Edwards, 1845
  Species: Myrianida sp.

      Genus: Exogone Örsted, 1845
  Species: Exogone naidina Örsted, 1845

Venomous. From 1 cm to over half a meter with several hundreds of segments. Body cylindrical to dorso-ventrally flattened in transverse section and anteriorly and posteriorly tapers to fine points.

      Genus: Glycera de Lamarck, 1818
  Species: Glycera lapidum Quatrefages, 1866

Abundant in shallow waters. Difficult to identify to species level. In transverse sections body characteristically rectangular. From few millimeters to 30-40cm, with anterior end larger and the posterior end tapering.

      Genus: Nephtys Cuvier, 1817
  Species: Nephtys ciliata (O.F. Müller, 1776)
  Species: Nephtys incisa Malmgren, 1865
  Species: Nephtys paradoxa Malm, 1874
  Species: Nephtys pente Rainer, 1984

      Genus: Aglaophamus Kinberg, 1865
  Species: Aglaophamus malmgreni (Théel, 1879)

Paddle-worms. With large and flattened dorsal cirri. Vary in size from few millimeters to over a meter and in number of segments from 20 to thousand.

      Genus: Phyllodoce de Lamarck, 1818
  Species: Phyllodoce (Anaitides) groenlandica Örsted, 1842

      Genus: Eteone de Savigny, 1822
  Species: Eteone flava (Fabricius, 1780)
  Species: Eteone longa (Fabricius, 1780)
  Species: Eteone spetsbergensis Malmgren, 1865
  Species: Eteone barbata Malmgren, 1865

      Genus: Eumida Malmgren,1865
  Species: Eumida arctica (Annenkova, 1946)

Body surface covered by conspicuous macro- and microtubercles and/or papillae, which are often segmentally arranged in transverse rows. Small to medium sized. Short and grub-like with up to 30 segments or elongated and slender with more segments.

      Genus: Sphaerodoridium Lützen,1961
  Species: Sphaerodoridium sp.

      Genus: Sphaerodoropsis Hartman & Fauchald, 1971
  Species: Sphaerodoropsis sp.
  Species: Sphaerodoropsis philippi (Fauvel, 1911)