The functioning of the statocysts ofOctopus vulgaris

Abstract

Octopuses with both statocysts removed were disorientated when swimming. Only slight disorientations were seen when they walked on horizontal surfaces. Vertical surfaces were sometimes treated as if they were horizontal. Blind octopuses maintained their equilibrium when walking or swimming. Blind octopuses with statocysts removed showed greater disorientation when walking than octopuses with only the statocysts removed, but walked the right way up. There is, therefore, some sensory system(s) other than the statocysts and eyes involved in equilibral responses. When swimming, blind octopuses with both statocysts removed showed differences from those with only the statocysts removed, not by being more disorientated but by showing less frequent changes in the position of the funnel. Unilateral removal of a statocyst caused little disturbance of the behavior of an octopus. The probable regions of the brain concerned with the integration of equilibral responses are indicated.