| Macrostomum viride (1) Beneden E, 1870 | 1913 or earlier | | | found in the country of Belgium. |
| Prorhynchus stagnalis Schultze, 1851 | 1913 or earlier | | | |
| Rhynchodemus terrestris (Müller, 1773) | 1940 or earlier | | | terrestrial. |
| Polycelis nigra (Müller, 1774) | 1911-1935 | | | |
| Polycelis cornuta Johnston, 1822 | 1911-1935 | | | |
| Euplanaria gonocephala (Duges, 1830) | 1911-1935 | | | |
| Crenobia alpina (Dana, 1766) | 1911-1935 | | | |
| Planaria torva (Müller, 1773) | 1941 or earlier | | | ......, Belgien, nur in stehendem Wasser von pH über 7, ausnahmsweise auch in Brackwasser. |
| Rhynchodemus sylvaticus (Leidy, 1852) | 1981 or earlier | | | Early records of this species were mostly from greenhouses, but the Belgium and British populations were well established outdoors. |
| Bipalium kewense Moseley, 1878 | 2021 or earlier | | | |
| Dolichoplana striata Moseley, 1877 | | | | |