(A) Two adult Bothrioplana semperi (Bothrioplanida) swimming in different directions. Adults are approximately 1.5 mm outstretched. Collected from near Saw Mill brook, Estabrook Woods, Concord, MA. (B) Adult of an undescribed species of Polystyliphora (Proseriata), collected from the interstices of marine sand in Bocas del Toro, Panama. Scale bar unavailable. (C) Adult specimen of an undescribed blind species of Microdalyellia (Rhabdocoela), collected in fresh water from Mt. Blue Spring, Wompatuck State Park, MA. (D) Adult, undetermined species of Nannorhynchides (Rhabdocoela), collected in brackish water at low tide near Sage Lot Pond outlet, Mashpee, MA. Scale bars: 100 µm. Samples in panels A, C and D photographed by Christopher E Laumer. Sample in panel B photographed by Marco Curini-Galletti.