Fig. 2. Development of the electric organ (EO) from larval to adult stages. (A) Area of the fish body occupied by the EO (expressed as a percentage of the cross-sectional area) as a function of the distance from the jaw (expressed as a percentage of the fish length). The area of the fish body occupied by the EO in the rostral half of the fish body is greater in larvae (30 mm) than in juveniles (65 mm), and the contrary holds for the caudal half of the fish body. (B) For all studied fish (28, 68 and 185 mm), the density of electrocytes (expressed as the number of electrocytes per 1% of fish body length) increases from the rostral to the tail regions.