Fig. 6From: Crown-of-thorns starfish have true image forming visionBehavioural results: black circle on a white background. a-e Starfish were attracted to circles with initial angular sizes of 14° or larger. All stimuli were attached to a Plexiglas sheet using Velcro, and the entire sheet was placed in the behavioural arena. f Starfish where not attracted to the control stimulus, the Plexiglas sheet alone, without stimulus patterns. For more details on the circular plots see caption of Fig. 2. A summary of the circular statistics is given in Table 1 Back to article page