ELECTRIC FISH 



They may be as much as six feet long. Their electrical 

 capacity, and the way in which they use it, are far beyond 

 those of any other fish. They, like the torpedo, have 

 two voluminous organs symmetrical and of the same 

 size, but these organs have a different situation in the 

 body, and their size is proportionately greater. Each 

 consists of a thick mass, situated in the sides but con- 

 tinuing under the belly and reaching from the fore part 

 of the trunk to near the tail. They are made up as 

 usual of little prismatic columns placed side by side and 

 subdivided into disks, but the columns are divided 

 horizontally and not vertically. So, compared with the 

 torpedo, we find a difference in the direction and posi- 

 tion of the batteries and consequently a difference in 

 polarity. In the torpedo, the positive pole is above, 

 the negative below. In the electric eel, the positive 

 pole is in front and the negative pole behind. 



Not long ago, I owned three living electric eels which 

 had come from Guiana, and kept them several weeks in 

 a tank, unfortunately not long enough for all the 

 observations I hoped to make. Usually they lay upon 

 the bottom, getting up at intervals to swim about the 

 tank, then sinking again to the bottom. They then 

 showed, as they moved easily about, how little resem- 

 blance they really have to the eels. Certainly they are 

 long and cylindrical and swim with a flexible and ser- 

 pentine movement, and they are brownish-grey in 

 colour, but in every other respect they differ. The 

 head is broader and larger, flat on the top, and shaded 

 underneath with a fiery red hue which continues under 

 the neck and the body. All along the lower side of the 

 tail runs a fringe-like anal fin, which aids in swimming. 

 Their method of swimming is as rare as it is curious, for 

 it is helped by the possession of this supple lower fin, 

 broad and long at the same time, and this peculiar 

 feature is seldom met with. According to the rhythm 

 and direction of the movements, the fish goes forwards 

 or backwards. When we watch its evolutions, we enjoy 



■63 



