Acoela (basis of record)
Acrorhynchides Strand, 1928 (additional source)
Acrorhynchides robustus (Karling, 1931) Strand, 1928 (additional source)
Anaperidae Dörjes, 1968 accepted as Convolutidae Graff, 1905 (additional source)
Anaperus Graff, 1911 accepted as Thalassoanaperus Hernandez, 2018 (additional source)
Anaperus tvaerminnensis (Luther, 1912) accepted as Thalassoanaperus tvaerminnensis (Luther, 1912) (additional source)
Archilopsis Meixner, 1938 (additional source)
Astrotorhynchus Graff, 1905 (additional source)
Astrotorhynchus bifidus (McIntosh, 1874) Graff, 1905 (additional source)
Baicalellia Nasonov, 1930 (additional source)
Baicalellia brevituba (Luther, 1918) Nasonov, 1930 (additional source)
Brinkmanniella Luther, 1943 (additional source)
Brinkmanniella macrostomoides Luther, 1948 (additional source)
Byrsophlebidae Graff, 1882 (additional source)
Cheliplana de Beauchamp, 1927 (additional source)
Cheliplana stylifera Karling, 1949 (additional source)
Childiidae Dörjes, 1968 accepted as Mecynostomidae Dörjes, 1968 (additional source)
Cicerinidae Meixner, 1928 (additional source)
Coelogynopora Steinböck, 1924 (additional source)
Coelogynopora gynocotyla Steinböck, 1924 (additional source)
Coelogynoporidae Karling, 1966 (additional source)
Cylindrostoma Ørsted, 1845 (additional source)
Cylindrostoma fingalianum (Claparède, 1861) (basis of record)
Cylindrostomidae Reisinger, 1924 accepted as Pseudostomidae Graff, 1904-08 (additional source)
Dalyelliidae Graff, 1905 (additional source)
Dalyellioida accepted as Dalytyphloplanida (basis of record)
Diascorhynchidae Meixner, 1928 (additional source)
Diascorhynchus Meixner, 1928 (additional source)
Dolichomacrostomidae Rieger, 1971 (additional source)
Eukalyptorhynchia (basis of record)
Gnathorhynchidae Meixner, 1929 (additional source)
Gnathorhynchus Meixner, 1929 (additional source)
Gnathorhynchus conocaudatus Meixner, 1929 (additional source)
Graffillidae Graff, 1905 (additional source)
Halammovortex Karling, 1943 (additional source)
Halammovortex macropharynx (Meixner, 1938) Karling, 1943 (additional source)
Jensenia Graff, 1882 (additional source)
Jensenia angulata (Jensen, 1878) Graff, 1882 (additional source)
Kalyptorhynchia (additional source)
Karkinorhynchidae Meixner, 1928 (additional source)
Leptoplanidae Stimpson, 1857 (additional source)
Listea Ax & Heller, 1970 (additional source)
Listea simplex Ax & Heller, 1970 (additional source)
Macrostomida (basis of record)
Macrostomidae Beneden E., 1870 (additional source)
Macrostomum Schmidt, 1848 (additional source)
Maehrenthalia Graff, 1905 (additional source)
Mecynostomidae Dörjes, 1968 (additional source)
Mecynostomum Beneden E., 1870 (additional source)
Mecynostomum auritum (Schultze, 1851) (additional source)
Messoplana Den Hartog, 1966 accepted as Ceratopera Den Hartog, 1964 (additional source)
Messoplana elegans (Luther, 1948) Den Hartog, 1966 accepted as Ceratopera elegans (Luther, 1948) Van Steenkiste & Leander, 2018 (additional source)
Minona Marcus, 1946 (additional source)
Monocelididae Hofsten, 1907 (additional source)
Monocelis Ehrenberg, 1831 (additional source)
Monocelis fusca Örsted, 1843 (additional source)
Monocelis lineata (Müller, 1773) Oersted, 1843 (additional source)
Notocaryoplanella Ax, 1956 accepted as Notocaryoplana Steinböck, 1935 (basis of record)
Notocaryoplanella glandulosa (Ax, 1951) accepted as Notocaryoplana arctica Steinböck, 1935 (basis of record)
Notoplana Laidlaw, 1903 (basis of record)
Notoplana atomata (Müller OF, 1776) (basis of record)
Otocelididae Westblad, 1948 (additional source)
Otoplanidae Hallez, 1892 (additional source)
Paracicerina Meixner, 1928 (additional source)
Paraschizorhynchoides Schilke, 1970 (additional source)
Paraschizorhynchoides glandulis Schilke, 1970 (additional source)
Paratomella Dörjes, 1966 (additional source)
Paratomellidae Dörjes, 1966 (additional source)
Philactinoposthia Dörjes, 1968 (additional source)
Philactinoposthia saliens (Graff, 1882) (additional source)
Placorhynchidae Meixner, 1938 (additional source)
Placorhynchus Karling, 1931 (additional source)
Placorhynchus octaculeatus Karling, 1931 (additional source)
Plagiostomidae (additional source)
Plagiostomum Schmidt, 1852 (additional source)
Plagiostomum vittatum (Frey & Leuckart, 1847) Jenssen, 1878 (additional source)
Pogaina Marcus, 1954 (additional source)
Pogaina suecica (Luther, 1948) Marcus, 1954 (additional source)
Polycladida (basis of record)
Procerodes Girard, 1850 (additional source)
Procerodes littoralis (Strøm, 1768) (additional source)
Procerodidae Diesing, 1862 (additional source)
Prognathorhynchus Meixner, 1929 (additional source)
Prognathorhynchus canaliculatus Karling, 1947 (additional source)
Prolecithophora (basis of record)
Promesostoma Graff, 1882 (additional source)
Promesostoma caligulatum Ax, 1952 (additional source)
Promesostoma gracilis Ax, 1951 accepted as Promesostoma gracile Ax, 1951 (additional source)
Promesostoma marmoratum (Schultze, 1851) Graff, 1882 (additional source)
Promesostoma meixneri Ax, 1951 (additional source)
Promesostoma rostratum Ax, 1951 (additional source)
Promesostomidae Graff, 1882 (additional source)
Promonotus Beklemischev, 1927 (additional source)
Promonotus schultzei Meixner, 1943 (additional source)
Proseriata (additional source)
Provortex Graff, 1882 (additional source)
Provortex affinis (Jensen, 1878) Graff, 1882 (additional source)
Provortex balticus (Schultze, 1851) Graff, 1882 (additional source)
Provortex karlingi Ax, 1951 (additional source)
Provorticidae Beklemischev, 1927 (additional source)