Optic and Static Contributions to Ocular Counter-Rotation in Carp

1. This paper describes a method for measuring static eye reflexes in restrained but unanaesthetized fish. 2. Ocular counter-rotation in response to movement round the transverse axis of the body was studied in detail by means of denervation experiments and changes in the direction of incident light. 3. Both body position, measured by the labyrinths and light direction, measured by the eyes, contribute to counter-rotation. 4. Round about the normal attitude of the fish ocular counter-rotation is proportional to the angular deviation of the body from horizontal. 5. The gain of the system measured this way can change according to the excitability of the fish but the proportional relationship is retained.