Optomotor Responses and Nystagmus in Intact, Blinded and Statocystless Cuttlefish (Sepia Officinalis L.)

Evidence is reviewed confirming that the eyes of Sepia move under the influence of gravity, angular acceleration and visual receptors. Visual nystagmus and optomotor responses are described in free-swimming Sepia; these survive bilateral destruction of the statocysts, though they are abolished by blinding. Post-rotatory nystagmus is shown by intact animals in a plain background; in bilaterally blinded animals there are post-rotatory movements of the head. These responses disappear if the statocysts are removed. The post-rotatory nystagmus of intact animals is almost completely suppressed by visual cues. Other effects of blinding and statocyst removal are described.