| Family | Common Name | Selected Genus and Species | Image |
| Actinoposthiidae | Acoel | Actinoposthia caudata |  |
| Antigonariidae | Acoel | Antigonaria arenaria |  |
| Antroposthiidae | Acoel | Antroposthia axi |  |
| Convolutidae | Acoel | Neochildia fusca |  |
| Dakuidae | Acoel | Philactinoposthia multipunctata |  |
| Diopisthoporidae | Acoel | Diopisthoporus psammophilus |  |
| Hallangiidae | Acoel | Hallangia proporoides |  |
| Hofsteniidae | Acoel | Hofstenia miamia |  |
| Isodiametridae | Acoel | Isodiametra pulchra |  |
| Mecynostomidae | Acoel | Childia trianguliferum |  |
| Nadinidae | Acoel | Nadina minuta |  |
| Otocelididae | Acoel | Philocelis robrochai |  |
| Paratomellidae | Acoel | Paratomella rubra |  |
| Proporidae | Acoel | Proporus carolinensis |  |
| Solenofilomorphidae | Acoel | Solenofilomorpha justinei |  |
| Taurididae | Acoel | Taurida fulvomaculata |  |
