The larval settling response of the lined chiton Tonicella lineata

The lined chiton Tonicella lineata (Wood, 1815) is found on enerusting coralline algae in the lower rocky intertidal zone of Oregon and San Juan Island, Washington, USA. An encrusting coralline alga is the major food item of this chiton. Experiments were performed to test the settling response of T. lineata larvae to various algae and other substrata. In these experiments, the larvae would settle only on pieces of encrusting coralline algae and piecesof ceramic roofing tile soaked in a coralline algal extract. The settling stimulus is probably chemical in nature, and is inactivated by boiling. In laboratory cultures, normal development stops at the trochophore stage (110 to 160 h, depending on the temperature). Metamorphosis and further development will take place only after stttlement on encrusting coralline algae.