| Macrostomorpha Macrostomidae Beneden E, 1870 | | w | other taxonomic work | |
| Macrostomum intermedium Tu, 1934 | | w | latest taxonomic authority | |
| Macrostomum japonicum Okugawa, 1930 | | w | latest taxonomic authority | |
| Macrostomum nassonovi (Nasonov, 1921) | [with synonyms] | w | latest taxonomic authority | |
| Axia gieysztori (Ferguson, 1939) | | w | primary taxonomic authority (describer) | |
| Macrostomum appendiculatum (1) finnlandensis Ferguson, 1940 | | w | primary taxonomic authority (describer) | 32-34, Fig 12-13 |
| Macrostomum appendiculatum (1) sillimani Ferguson, 1939 | | w | primary taxonomic authority (describer) | |
| Macrostomum beauchampi Ferguson, 1939 | | w | primary taxonomic authority (describer) | |
| Macrostomum carolinense Ferguson, 1940 | [with synonyms] | w | primary taxonomic authority (describer) | 29-32 |
| Macrostomum collistylum Ferguson, 1939 | | w | primary taxonomic authority (describer) | |
| Macrostomum curvistylum Ferguson, 1939 | | w | primary taxonomic authority (describer) | |
| Macrostomum finnlandense (Ferguson, 1940) | [with synonyms] | w | primary taxonomic authority (describer) | |
| Macrostomum frigorophilum (Ferguson, 1940) | [with synonyms] | w | primary taxonomic authority (describer) | |
| Macrostomum gieysztori Ferguson, 1939 | [with synonyms] | w | primary taxonomic authority (describer) | |
| Macrostomum gilberti Ferguson, 1939 | | w | primary taxonomic authority (describer) | |
| Macrostomum glochistylum Ferguson, 1939 | [with synonyms] | w | primary taxonomic authority (describer) | |
| Macrostomum glocostylum Ferguson, 1939 | | w | primary taxonomic authority (describer) | 197-199 figs. 13-17 |
| Macrostomum graffi Ferguson, 1939 | | w | primary taxonomic authority (describer) | |
| Macrostomum granulophorum Ferguson, 1940 | [with synonyms] | w | primary taxonomic authority (describer) | |
| Macrostomum lewisi Ferguson, 1939 | | w | primary taxonomic authority (describer) | |
| Macrostomum recurvostylum Ferguson, 1940 | [with synonyms] | w | primary taxonomic authority (describer) | |
| Macrostomum reynoldsi Ferguson, 1939 | | w | primary taxonomic authority (describer) | |
| Macrostomum riedeli Ferguson, 1940 | | w | primary taxonomic authority (describer) | |
| Macrostomum ruebushi carolinensis Ferguson, 1940 | | w | primary taxonomic authority (describer) | 129: 27-30 |
| Macrostomum ruebushi crenatostylum Ferguson, 1940 | | w | primary taxonomic authority (describer) | 129: 30-32 |
| Macrostomum ruebushi finnlandensis Ferguson, 1940 | | w | primary taxonomic authority (describer) | 32-34 |
| Macrostomum ruebushi frigorophilum Ferguson, 1940 | | w | primary taxonomic authority (describer) | 34-37 |
| Macrostomum ruebushi granulophorum Ferguson, 1940 | | w | primary taxonomic authority (describer) | 37-41 |
| Macrostomum ruebushi recurvostylum Ferguson, 1940 | | w | primary taxonomic authority (describer) | 41-44 |
| Macrostomum ruebushi shenandoahensis Ferguson, 1940 | | w | primary taxonomic authority (describer) | 44-45 |
| Macrostomum ruebushi truncatum Ferguson, 1940 | | w | primary taxonomic authority (describer) | 45-48 |
| Macrostomum shenandoahense Ferguson, 1940 | [with synonyms] | w | primary taxonomic authority (describer) | |
| Macrostomum tennesseense Ferguson, 1940 | | w | primary taxonomic authority (describer) | |
| Macrostomum truncatum Ferguson, 1940 | [with synonyms] | w | primary taxonomic authority (describer) | |
| Macrostomum vejdovskyi Ferguson, 1940 | [with synonyms] | w | primary taxonomic authority (describer) | |
| Promacrostomum gieysztori (Ferguson, 1939) | | w | primary taxonomic authority (describer) | |
| Macrostomum beaufortense Ferguson, 1937 | [with synonyms] | w | other taxonomic work | pt III |
| Macrostomum glochostylum Ferguson, 1939 | | w | primary taxonomic authority (describer) | 198 |
| Macrostomidae Macrostomum Schmidt, 1848 | [with synonyms] | w | other taxonomic work | |
| Macrostomum appendiculatum Fabricius, 1826 | [with synonyms] | w | other research on this sp. | |
| Macrostomum appendiculatum (1) stirewalti Jones & Ferguson, 1941 | | w | other taxonomic work | |
| Macrostomum elgonense (de Beauchamp, 1936) | [with synonyms] | w | other taxonomic work | pt III |
| Macrostomum ruebushi Ferguson, 1940 | | w | other taxonomic work | |
| Macrostomum boreale Riedel, 1932 | [with synonyms] | w | other taxonomic work | pt III |
| Macrostomum gracile (1) Pereyaslawzewa, 1892 | | w | other taxonomic work | pt IV |
| Macrostomum infundibuliferum Plotnikow, 1905 | | w | other taxonomic work | pt IV |
| Macrostomum stylopencillum Jones, 1940 | | w | primary taxonomic authority (describer) | pt VII |
| Macrostomum ruebushi finnlandense Ferguson, 1940 | | w | primary taxonomic authority (describer) | p. 4 in Supporting Information |