| Microstomum davenporti Graff, 1911 | between May and Aug 1907 | | | |
| Proxenetes modestus Graff, 1911 | between May and Aug 1907 | | | 5 specimens |
| Woodsholia lilliei Graff, 1911 | between May and Aug 1907 | | | |
| Phonorhynchus helgolandicus (Metschnikow, 1865) | between May and Aug 1907 | | | |
| Plagiostomum stellatum Graff, 1911 | between May and Aug 1907 | | | Grass Island in Zostera |
| Plagiostomum morgani Graff, 1911 | between May and Aug 1907 | | | |
| Myrmeciplana elegans Graff, 1911 | prior to 1911 | | coarse sand | |
| Myrmeciplana sp. Bush, 1964 | 1963 | | | may be Myrmeciplana, "but have a pair of eyes in most cases". |
| Euplana gracilis (Girard, 1850) | 1935 or earlier | | | secured specimens from invertebrate staff at Woods Hole in 1935. Found in abundance in the Eel Pond on wharves and pilings among masses of hydroids and sponges,. |