We wish to learn how the nervous system of the weakly electric mormyrid fish constructs an image of its world through its electrosense. Our main focus is, therefore, on the central nervous system. However, our work on the brain will be most meaningful if a clear understanding of the overall performance of the system is obtained. We have, therefore, done and plan to do behavioral studies on the electrosensory system. We also need to know the input to the CNS which occurs following the discharge of the electric organ and how this is distorted by objects in the environment. In pursuit of this latter goal we have done and plan studies on the generator itself, the distribution of voltages across the skin and the responses of electroreceptors to these voltages. Within the CNS we are working on the Posterior Lateral Line Lobe (PLLL) where primary electroreceptor afferents terminate and on the valvula cerebelli. The latter structure is the extraordinary giganto cerebellum of mormyrids.