[Differenciation of electroreceptors in Marcusenius sp. (Mormyrides) and Eigenmannia virescens (Gymnotides), electric fishes with weak discharges].

Having recently succeeded in breeding two species of weakly electric fish, Eigenmannia virescens and Marcusenius sp., the ontogeny of certain electroreceptors, the tuberous organs, of these fish was studied in detail. At 27 degrees C, eight day old larvae possess electroreceptors which are fully differentiated and appear to be functional. At this stage the larvae also show the first electric discharge.