A large, slightly flattened worm, which can be grey to reddish brown in colour. A notable feature are the two eyes and 5 short tentacles on the head end. There are red gills from about the middle of the body to the head.
Subtidal to low intertidal, usually found under rocks, where it sometimes builds a protective tube of loosely stuck together mud and shells.
A predator and scavenger of other invertebrates.
Some members of the family can be very large.
Photo Credit: Rod Morris. Photos can be purchased from https://www.rodmorris.co.nz/