LEATHER LIMPET - RARELY SEEN LITTLE GEM

LEATHER LIMPETS, Onchidella borealis, are tiny mollusks (about .5 inches) that are often overlooked because of their size and cryptic coloration.  They are closely related to land slugs and like their relatives have their eyes on the tips of their tentacles. They have no shell.  Lungs gather oxygen from the air and there are no gills.  When submerged they may associate with air bubbles for oxygen.  These are high intertidal inhabitants feeding on both micro and macro algae.  The edge of the foot is decorated with large papillae or knobs which produce noxious chemicals that repel predators such as sea stars and small crabs.   Six to 40 eggs are laid in a gelatinous mass usually attached to seaweed holdfasts.  Development of larval stages takes place in the egg and young juveniles hatch out and crawl away; there is no planktonic stage.
The best place to look for these little gems is in communities of Fucus (rockweed) where they will be actively feeding at low tide.  They are more often seen on cool cloudy mornings that hot sunny ones.  Take a magnifying lens for a close look.