| Hoploplana inquilina (Wheeler, 1894) | 1938 | | | collected by Dr. Pearse on the Massachusetts Coast commensal with snails Busycon (larger form of Hoploplana inquilina) and Thais floridana floridana (small form of Hoploplana inquilina). |
| Macroatrium setosum Riser, 1981 | late 1960 s | low intertidal | | collected from a number of beaches in Massachusetts. |
| Notoplana atomata (Müller, 1776) | prior to 1940 | | | Hyman reviewed unidentified vials sent to US National Museum all of which are N. atomata from points off the coast of Massachusetts and from Casco Bay, Maine. |
| Cylindrostoma atlanticum Beltagi, 2005 | May 2000 | 50-170 cm at low tide | algae (Sagassum vulgare, Cyctoseira murica, Entermorpha sp) living on sandy bottom | "near the coast ... at Boston"; map shows Boston and Woods Hole labeled but no collection markers |