EXPERIMENTS ON HOMING IN LIMPET SIPHONARIA-NORMALIS

Summaryo1.Individuals of the pulmonate limpet, Siphonaria normalis, found intertidally on Coconut Island, Oahu, Hawaii, were most active as the tide rose and fell past their rocks; consistent homing to scars in the rocks occurred.2.Rock rotation experiments eliminated the possibility that distant clues (polarized light, sun or moon position, coastal landmarks, sky brightness, gravity) are involved in homing. Experimental animals were able to return home when the rocks were rotated 90 degrees in the horizontal plane or 180 degrees in the vertical plane while the limpets were away from home.3.A series of displacement experiments eliminated dead-reckoning as a mechanism in homing and confirm that it is not necessary for animals to return home along their outgoing trails. When animals were displaced to various positions around their homes, those snails which were placed in areas over which they had been observed moving on previous occasions returned home directly. Limpets failed to home when placed in areas in which they had not been previously seen. Of the latter several were transplanted a second time onto areas where they had been observed before and returned home directly.4.Detection of chemical information laid down on the rock during homing excursions and topographic memory remain as possible mechanisms involved in homing. © 1969.