Fish physiology

thumb|upright=1.2|A knollenorgan drawn by the German anatomist Viktor Franz, 1921. RC=receptor cell; b.m.= basal membrane; n=nerve. Line at top=skin surface.The organ is embedded in the skin of Mormyridae|mormyrid fishes, which actively electrolocate by generating brief electrical pulses with their electric organ. The returns from the pulses, distorted by any nearby objects such as prey, are detected by the knollenorgans distributed around the fish's body.