Biology/Natural History: Lives lower on rocks than does L. planaxis. Migrates up and down rocks with the tide. Crawl out of tidepools at night, in during the day. Often hide at low tide in cracks or barnacle shells. Muscular waves of foot travel from front to rear (retrograde). The waves on the two sides of the foot are out of phase with one another (ditaxic). Feeds mainly on diatom films, microscopic algae, lichens, etc. Will also feed on Pelvetia, Ulva, other larger algae. Breeds in all seasons except summer. Eggs are laid underwater, individually packaged in flattened capsules within a sausage-shaped gelatinous mass coiled in a spiral and holding over 2000 eggs. Leptasterias hexactis feeds on this snail. Eye anatomy is similar to that of the land snail Helix aspera. In Oregon over 10% of individuals harbor parasitic flukes.