| Convoluta karlingi Westblad, 1946 | Aug 5, 1936 | 4 m | coarse sand |  | 
| Anaperus tvaerminnensis (Luther, 1912) | prior to 1960 | 1 m | gyttja (A nutrient-rich sedimentary peat consisting mainly of plankton, other plant and animal residues, and mud) | North Tvarminne.  Vegetation zone: Krogarviken (?)  among Myriophyllum, etc. | 
| Prolecithoplana lutheri Karling, 1940 | prior to 1940 |  |  |  | 
| Mecynostomum auritum (Schultze, 1851) | prior to 1975 | shallow | sand | Baltic Sea, Tvärminne area. | 
| Pelophila lutheri (Westblad, 1946) | prior 1975 |  |  |  | 
| Pseudmecynostomum flavescens (Dörjes, 1968) | prior 1975 |  | sand | shallow water | 
| Pseudmecynostomum westbladi Dörjes, 1968 | prior 1975 | 1-2 m | sand |  | 
| Mecynostomum lutheri (Westblad, 1946) | 1948 or earlier | 20 m |  | North Tvärminne, waterway between Langholmen and Kvarnskär. | 
| Anaperus tvaerminnensis (Luther, 1912) | prior to 1960 | 0.5 m | sand | near the wastewater discharge of the biological station. | 
| Haplovortex brevitubus (Luther, 1918) | 1918 or earlier |  |  |  | 
| Stenostomum bryophilum Luther, 1960 | Aug 18, 1953 |  |  | moss on rocks.  Several, collected by F. Papi. | 
| Stenostomum karlingi Luther, 1960 | prior to 1960 |  |  | coastal ground water, Karling. | 
| Stenostomum karlingi Luther, 1960 | prior to 1960 |  |  | In bank meadows, on vegetation (Scirpus uniglumis, Juncus Gerardi, Agrostis stolonifera and Spergula salina) above the water level. | 
| Macrostomum balticum Luther, 1947 | prior to 1960 | 0.5 m | sand | all specimens found between June and August. | 
| Macrostomum balticum Luther, 1947 | Aug 9, 1929 | 1 m | sand |  | 
| Promesostoma marmoratum (Schultze, 1851) | prior to 1943 |  |  | a large number of individuals found. | 
| Hangethellia calceifera Karling, 1940 | 1934-1937 | 6 m |  | summer collection. | 
| Anthopharynx vaginatus Karling, 1940 | 1940 or earlier | 5-22 m | fine sand | detritus rich fine sand.  found at depths up to 22 m, but seems to prefer 5-10 m. | 
| Prognathorhynchus campylostylus Karling, 1947 | Aug-Sep 1936 | 9-12 m | sand | Einige Exemplare wurden bei Tvärminne, Henriksberg aus detritusreichem Sand in einer Tiefe von 9-12 m gefunden.  Die Bodenart war hier sehr reich an sowohl Kleinturbellarien als Polychäten, Kinorhynchen, Halacariden und Nematoden. | 
| Odontorhynchus lonchiferus Karling, 1947 | 1947 or earlier | 20 m | mud | Einige Exemplare stammen aus denselben Proben wie Pr. campylostylus (vgl. oben), einige andere aus Schlick bei Tvärminne, Porsskär in einer Tiefe von etwa 20 m. | 
| Haloplanella obtusituba Luther, 1946 | Jan 7, 1944 | 25 m | Gyttja, loam, sand | 3 specimens collected between Tvärminne and Järnön Island by Purasjoki.  5.59 o/oo. | 
| Haloplanella curvistyla Luther, 1946 | 1946 or earlier | 0.5 m | sand | Dr. Tor G. Karling and the author collected this near Tvärminne in June and July. | 
| Beklemischeviella angustior Luther, 1943 | 1997 |  |  | Ostsee.  Finnischer Meerbusen.  Umgebung von Tvaerminne bis in 34 m Wassertiefe.  Eigene Funde am Sandstrand von Lappvik. | 
| Haloplanella curvistyla Luther, 1946 | 1963 or earlier |  |  | SW von Kvarnskär. | 
| Bresslauilla relicta Reisinger, 1929 | 1930 or earlier |  |  | 15º C | 
| Thylacorhynchus pyriferus Karling, 1950 | 1950 or earlier | 1 - 16 m |  | Detritusreicher, meist feinkörniger Sand an folgenden Stellen in der Umgebung Tvärminne:  Lappvik Storfjärd 1-10m, zwischen Brännskär und Sundholm 6m, Henriksberg 9-10m, Stenskär Leuchtturm 16m. | 
| Thylacorhynchus conglobatus Meixner, 1928 | 1950 or earlier | 5 m |  | Tvärminne, Henriksburg, aus Bodensand von wechselnder Körnergrösse in einer Tiefe von etwa 5 m, spärlich. | 
| Microdalyellia armigera (Schmidt, 1862) | 1955 or earlier |  |  | Felstümpel auf den Schären, mit höherem Pflanzenwuchs, manchmal in grosser Anzahl | 
| Microdalyellia picta (Schmidt, 1848) | Jun 8, 1951 |  |  | Tvärminne, Kasbergskärret und Hästhagen, Moor mit Caltha, Hippuris, Sparganium minimum etc., 5-20 cm tief. Torfgräben und Tümpel in Laubwald, viel Fadenalgen, am Boden totes Laub, am Rande Sphagnum und Amblystegium. | 
| Microdalyellia rossi (Graff, 1911) | 1955 or earlier |  |  | Tvärminne, Hästhagen, kleiner Graben mit fliessendem Wasser auf humusreichen Waldboden, Ende April bis Mitte Mai, Wassertemp, 6-9 1/2º C. |