Sole translucent white with opaque white spots on both typical and melanistic specimens.
Narrow furrowed foot with rounded flexible anterolateral lobes (1) is well adapted for gripping and moving among fine strands of weed on which it lives.
Posterior pedal gland (2) exudes mucus that is formed into a thread in ciliated groove running to posterior of foot; thread hardens on contact with sea water and is used to secure the animal and assist movement between different levels.

Shell height 1.95 mm, Weymouth, England, April 2012.