Tritonia swimming: triggering of a fixed action pattern.
D000818:Animals; D001522:Behavior, Animal / Q000502:physiology*; D002490:Central Nervous System / Q000502:physiology; D007323:Instinct / Q000502:physiology*; D008124:Locomotion; D008974:Mollusca / Q000033:anatomy & histology / Q000502:physiology*