| Family | Common Name | Selected Genus and Species | Image |
|---|---|---|---|
| Bothrioplanidae | Freshwater Flatworm | Bothrioplana semperi | |
| Family | Common Name | Selected Genus and Species | Image |
|---|---|---|---|
| Dolichomacrostomidae | Flatworm | Paromalostomum dubium |  |
| Microstomidae | Flatworm | Microstomum afzelii |  |
| Family | Common Name | Selected Genus and Species | Image |
|---|---|---|---|
| Fecampiidae | Fluke | Fecampia erythrocephala |  |
| Genostomatidae | Fluke | Genostoma inopinatum |  |
| Notenteridae | Fluke | Notentera ivanovi |  |
| Piscinquilinidae | Fluke | Piscinquilinus subcutaneus |  |
| Urastomidae | Fluke | Urastoma cyprinae |  |
| Family | Common Name | Selected Genus and Species | Image |
|---|---|---|---|
| Gnosonesimidae | Turbellarian Worm | Gnosonesima brattstroemi |  |
| Family | Common Name | Selected Genus and Species | Image |
|---|---|---|---|
| Haplopharyngidae | Free-living Flatworm | Haplopharynx quadristimulus |  |
| Macrostomidae | Fluke Free-living Flatworm | Macrostomum lignano |  |
| Family | Common Name | Selected Genus and Species | Image |
|---|---|---|---|
| Catenulidae | Flatworm | Catenula lemnae |  |
| Chordariidae | Flatworm | Chordarium europaeum |  |
| Leimacopsidae | Flatworm | Leimacopsis terricola |  |
| Retronectidae | Flatworm | Retronectes thalia |  |
| Stenostomidae | Flatworm | Stenostomum simplex |  |
| Tyrrheniellidae | Flatworm | Tyrrheniella sigillata |  |
| Family | Common Name | Selected Genus and Species | Image |
|---|---|---|---|
| Amyellidae | Flatworm | Chromyella saga | |
| Anocellidae | Flatworm | Anocellidus profundus |  |
| Anonymidae | Flatworm | Marcusia alba |  |
| Apidioplanidae | Flatworm | Apidioplana apluda | |
| Boniniidae | Flatworm | Boninia antillarum |  |
| Callioplanidae | Flatworm | Callioplana marginata |  |
| Candimboididae | Flatworm | Candimboides cuneiformis | |
| Cestoplanidae | Flatworm | Cestoplana rubrocincta |  |
| Chromoplanidae | Flatworm | Chromoplana sirena |  |
| Cryptocelidae | Flatworm | Phaenocelis peleca |  |
| Dicteroidae | Flatworm | Dicteros pacificus | |
| Didangiidae | Flatworm | Didangia mactanensis |  |
| Diposthidae | Flatworm | Diposthus popeae |  |
| Discocelidae | Flatworm | Adenoplana obovata |  |
| Discocelididae | Flatworm | Discocelis tigrina |  |
| Discoprosthididae | Flatworm | Discoprosthides patagoniensis |  |
| Ditremageniidae | Flatworm | Ditremagenia macropharynx | |
| Enantiidae | Flatworm | Enantia spinifera |  |
| Euplanidae | Flatworm | Euplana gracilis |  |
| Euryleptidae | Flatworm | Prostheceraeus roseus |  |
| Euryleptididae | Flatworm | Euryleptides brasiliensis | |
| Faubelidae | Flatworm | Amyris favis | |
| Gnesiocerotidae | Flatworm | Gnesioceros sargassicola |  |
| Ilyplanidae | Flatworm | Ilyella gigas |  |
| Laidlawiidae | Flatworm | Laidlawia trigonopora | |
| Latocestidae | Flatworm | Latocestus brasiliensis |  |
| Leptoplanidae | Flatworm | Leptoplana tremellaris |  |
| Limnostylochidae | Flatworm | Limnoplana amara |  |
| Mucroplanidae | Flatworm | Mucroplana caelata | |
| Notoplanidae | Flatworm | Notoplana australis |  |
| Opisthogeniidae | Flatworm | Opisthogenia tentaculata | |
| Palauidae | Flatworm | Palaua tropica | |
| Pericelidae | Flatworm | Pericelis tectivorum |  |
| Planoceridae | Flatworm | Planocera graffii |  |
| Plehniidae | Flatworm | Plehnia ovatus |  |
| Pleioplanidae | Flatworm | Pleioplana atomata |  |
| Polyposthiidae | Flatworm | Polyposthides affinis |  |
| Prosthiostomidae | Flatworm | Prosthiostomum torquatum |  |
| Pseudocerotidae | Flatworm | Pseudobiceros hancockanus |  |
| Pseudostylochidae | Flatworm | Idioplana atlantica |  |
| Stylochidae | Flatworm | Stylochus pilidium |  |
| Stylochocestidae | Flatworm | Stylochocestus gracilis | |
| Stylochoididae | Flatworm | Stylochoides albus | |
| Stylochoplanidae | Flatworm | Armatoplana leptalea |  |
| Theamatidae | Flatworm | Theama mediterranea |  |
| Family | Common Name | Selected Genus and Species | Image |
|---|---|---|---|
| Multipeniatidae | Flatworm | Multipeniata batalanse |  |
| Plagiostomidae | Flatworm | Vorticeros praedatorium |  |
| Protomonotresidae | Flatworm | Porfirievia minima |  |
| Pseudostomidae | Flatworm | Pseudostomum klostermanni |  |
| Scleraulophoridae | Flatworm | Scleraulophorus cephalatus |  |
| Family | Common Name | Selected Genus and Species | Image |
|---|---|---|---|
| Prorhynchidae | Flatworm | Prorhynchus fontinalis |  |
| Family | Common Name | Selected Genus and Species | Image |
|---|---|---|---|
| Archimonocelidae | Flatworm | Archimonocelis scopulicola |  |
| Calviriidae | Flatworm | Calviria sublittoralis |  |
| Ciliopharyngiellidae | Flatworm | Ciliopharyngiella constricta |  |
| Coelogynoporidae | Flatworm | Pseudovannuccia hirutai |  |
| Meidiamidae | Flatworm | Meidiama uruguayensis | |
| Monocelididae | Flatworm | Monocelis fusca |  |
| Monotoplanidae | Flatworm | Monotoplana diorchis |  |
| Nematoplanidae | Flatworm | Nematoplana pullolineata |  |
| Otomesostomatidae | Flatworm | Baikalotomesostoma stomi |  |
| Otoplanidae | Flatworm | Otoplana labronica |  |
| Polystyliphoridae | Flatworm | Polystyliphora karlingi |  |
| Family | Common Name | Selected Genus and Species | Image |
|---|---|---|---|
| Acholadidae | Flatworm | Acholades asteris | |
| Actinodactylellidae | Flatworm | Actinodactylella blanchardi |  |
| Aculeorhynchidae | Flatworm | Aculeorhynchus glandulis |  |
| Bertiliellidae | Flatworm | Bertiliella bathycola |  |
| Byrsophlebidae | Flatworm | Byrsophlebs dubia |  |
| Cheliplanidae | Flatworm | Cheliplana euxeinos |  |
| Cicerinidae | Flatworm | Cicerina bicirrata |  |
| Crassicollidae | Flatworm | Crassicollum musculare |  |
| Cystiplanidae | Flatworm | Cystiplana rubra |  |
| Cytocystididae | Flatworm | Cystiplex axi |  |
| Dalyelliidae | Flatworm | Dalyellia viridis |  |
| Diascorhynchidae | Flatworm | Diascorhynchus bucina |  |
| Diceratocephalidae | Flatworm | Diceratocephala boschmai |  |
| Gnathorhynchidae | Flatworm | Prognathorhynchus sinensis |  |
| Graffillidae | Flatworm | Graffilla brauni |  |
| Hypoblepharinidae | Flatworm | Hypoblepharina difficilis | |
| Karkinorhynchidae | Flatworm | Karkinorhynchus primitivus bicirrata |  |
| Koinocystididae | Flatworm | Itaipusa sinensis |  |
| Kytorhynchidae | Flatworm | Kytorhynchus microstylus |  |
| Luridae | Flatworm | Luriculus australiensis |  |
| Nannorhynchididae | Flatworm | Nannorhynchides vividus |  |
| Nematorhynchidae | Flatworm | Nematorhynchus parvoacumine |  |
| Placorhynchidae | Flatworm | Placorhynchus octaculeatus |  |
| Polycystididae | Flatworm | Gyratrix hermaphroditus |  |
| Promesostomidae | Flatworm | Promesostoma marmoratum |  |
| Provorticidae | Flatworm | Pogaina sinensis |  |
| Psammorhynchidae | Flatworm | Psammorhynchus tubulipenis |  |
| Pterastericolidae | Flatworm | Pterastericola ramosa |  |
| Rhynchokarlingiidae | Flatworm | Riedelella terentyevi |  |
| Schizorhynchidae | Flatworm | Carcharodorhynchus nativus |  |
| Scutariellidae | Flatworm | Scutariella japonica |  |
| Solenopharyngidae | Flatworm | Pilamonila bimascula |  |
| Temnocephalidae | Flatworm | Temnocephala curvicirri |  |
| Trigonostomidae | Flatworm | Ceratopera gracilis |  |
| Typhloplanidae | Flatworm | Mesostoma ehrenbergii |  |
| Umagillidae | Flatworm | Syndesmis kurakaikina |  |
| Family | Common Name | Selected Genus and Species | Image |
|---|---|---|---|
| Bdellouridae | Flatworm | Bdelloura candida |  |
| Centrovarioplanidae | Flatworm | Centrovarioplana tenuis | |
| Cercyridae | Flatworm | Sabussowia ronaldi |  |
| Dimarcusidae | Flatworm | Hausera hauseri |  |
| Dendrocoelidae | Flatworm | Dendrocoelum cavaticum |  |
| Dugesiidae | Flatworm | Dugesia japonica |  |
| Geoplanidae | Land Flatworm | Obama burmeisteri |  |
| Kenkiidae | Flatworm | Sphalloplana mohri |  |
| Meixnerididae | Flatworm | Meixnerides armatus | |
| Planariidae | Flatworm | Polycelis felina |  |
| Procerodidae | Flatworm | Procerodes littoralis |  |
| Rhynchodemidae | Flatworm | Rhynchodemus sylvaticus |  |
| Uteriporidae | Flatworm | Uteriporus vulgaris |  |