These unsegmented worms are very thin and flat, allowing them to squeeze into the smallest crevice. They secrete mucous both to keep them moist and to enable them to glide over the surface of rocks. This worm is often pale in colour with darker speckles.

Under rocks in the mid to low intertidal and subtidal.

A predator, feeds on other worms and small crustaceans, by crawling over them and everting it's muscular pharynx over the prey.

Reproduces both sexually and asexually. Flatworms are capable of remarkable regeneration. This species is also known to carry the puffer fish toxin, tetrodotoxin.