Errantia
Errantia, occasionally Aciculata, is a subclass of polychaete worms. These worms are found worldwide in marine environments and brackish water.Orders
;Order Amphinomida
- Amphinomidae Savigny in Lamarck, 1818
- Euphrosinidae Williams, 1851
;Order Eunicida
- Dorvilleidae Chamberlin, 1919
- Eunicidae Berthold, 1827
- Hartmaniellidae Imajima, 1977
- Lumbrineridae Schmarda, 1861
- Oenonidae Kinberg, 1865
- Onuphidae Kinberg, 1865
;Order Phyllodocida
- Acoetidae Kinberg, 1856
- Alciopidae Ehlers, 1864
- Aphroditidae Malmgren, 1867
- Chrysopetalidae Ehlers, 1864
- Eulepethidae Chamberlin, 1919
- Glyceridae Grube, 1850
- Goniadidae Kinberg, 1866
- Hesionidae Grube, 1850
- Ichthyotomidae Eisig, 1906
- Iospilidae Bergstroem, 1914
- Lacydoniida Bergstroem, 1914
- Lopadorhynchidae Claparede, 1868
- Myzostomidae Benham, 1896
- Nautiliniellidae Miura and Laubier, 1990
- Nephtyidae Grube, 1850
- Nereididae Johnston, 1865
- Paralacydoniidae Pettibone, 1963
- Pholoidae Kinberg, 1858
- Phyllodocidae Oersted, 1843
- Pilargidae Saint-Joseph, 1899
- Pisionidae Southern, 1914
- Polynoidae Malmgren, 1867
- Pontodoridae Bergstroem, 1914
- Sigalionidae Malmgren, 1867
- Sphaerodoridae Malmgren, 1867
- Syllidae Grube, 1850
- Tomopteridae Johnston, 1865
- Typhloscolecidae Uljanin, 1878
;Incertae sedis
- Aberrantidae Wolf, 1987
- Nerillidae Levinsen, 1883
- Spintheridae Johnston, 1865
