The Responses of Snails to Polarized Light*†

Abstract

1. Experiments were performed to test whether the polarized light responses of the marine snail, Nassa obsoleta, are mediated by a polarizing analyser within the eye or by the pattern of intensities reflected from the substratum. 2. Snails able to see only the substratum orient at right angles to the plane of vibration of vertically incident polarized light. 3. Snails unable to see the substratum but able to see the overhead source of polarized light fail to orient to the polarized light 4. Implications regarding the rare occurrence of intra-ocular polarizing analysers and the improbability of extensive animal use of polarized light as a navigational aid are discussed.