ELECTRICAL GYMN0TE. 57 



in which space were thirty-four septa. The small 

 organ has the same kind of septa, in length passing 

 from end to end of the organ, and in breadth pass- 

 ing quite across : they run somewhat serpentine ; 

 not exactly in strait lines. Their outer edges ter- 

 minate on the outer surface of the organ, which is 

 in contact with the inner surface of the external 

 muscle of the fin, and their inner edges are in con- 

 tact with the centre muscles. They dhTer very 

 much in breadth from one another ; the broadest being 

 equal to one side of the triangle, and the narrowest 

 scarcely broader than the point or edge. They 

 are pretty nearly at equal distances from one an- 

 other, but much nearer than those of .the large 

 organ, being only about the fifty-sixth part of an 

 inch asunder : but they are at a greater distance 

 from one another towards the tail, in proportion to 

 the increase of breadth of the organ. The organ is 

 about half an inch in breadth, and has fourteen 

 septa. These septa, in both organs, are very ten- 

 der in consistence, being easily torn. They appear 

 to answer the same purpose as the columns in the 

 Torpedo ; making walls or hutments for the subdi- 

 visions, and are to be considered as making so 

 many distinct organs. These septa are intersected 

 transversely by very thin plates or membranes, 

 whose breadth is the distance between any two 

 septa, and therefore of different breadths in differ- 

 ent parts; broadest at that edge which is next to 

 the skin, and narrowest at that next the centre of 

 the body, or to the middle partition which divides 

 the two organs from one another. Their lengths 



