54 ELECTRICAL GYMNOTE. 



surface is a plane adapted to the partition which 

 divides the two organs from one another. The 

 edge next to the muscles of the back is very thin, 

 but the organ becomes thicker and thicker towards 

 its middle, where it approaches the centre of the 

 animal. It becomes thinner again towards the 

 lower surface or belly, but that edge is not so thin 

 as the other. Its union with the parts to which it 

 is attached is in general by a loose, but pretty 

 strong, cellular membrane ; except at the partition, 

 to which it is joined so close as to be almost inse* 

 parable. The small organ lies along the lower 

 edge of the animal, nearly to the same extent as 

 the other. Its situation is marked externally by 

 the muscles, which move the fin under which it lies. 

 Its anterior end begins nearly in the same line 

 with the large organ, and just where the fin begins. 

 It terminates almost insensibly near the end of 

 the tail, where the large organ also terminates. It 

 is of a triangular figure, adapting itself to the part 

 in which it lies. Its anterior end is the narrowest 

 part : toward the tail it becomes broader ; in the 

 middle of the organ it is thickest, and from thence 

 becomes gradually thinner to the tail, where it i§ 

 very thin, The two small organs are separated 

 from one another by the middle muscles, and by 

 the bones upon which the bones of the fins are ar- 

 ticulated. The large and the small organ on each 

 side, are separated from one another by a membrane, 

 the inner edge of which is attached to the middle 

 partition, and its outer edge is lost on the skin of 

 the animal. To expose the large organ to view ? 



