646 SUPPLEMENT ON 



lion and other circumstances. The greatest number of 

 them are either irregular hexagons or pentagons ; but 

 from the irregularity of some of them, it happens, that a 

 pretty regular quadrangular column is sometimes formed. 

 Their coats are very thin, and seem transparent, closely con- 

 nected with each other, and having a kind of loose network 

 of tendinous fibres passing transversely and obliquely be- 

 tween the columns, and uniting them more firmly together. 

 These are mostly observable where the large trunk of the 

 nerves pass. The columns are also attached by strong in- 

 elastic fibres passing directly from one to the other. 



The number of columns in the electric organ of different 

 torpedos varies according to the size of the fish. In a very 

 large one 1182 were reckoned, but in a fish about a foot and 

 a half long, there appear to be about 470 in each organ. 

 New ones appear to be formed on the exterior edges, as the 

 animal increases in growth. Each column is divided by 

 horizontal partitions, placed over each other, at very small 

 distances, and forming numerous interstices, which appear 

 to contain a fluid. These partitions consist of a very thin 

 transparent membrane. Their edges appear to be attached 

 to one another, and the whole is attached by means of a fine 

 cellular membrane to the inside of the columns. 



The number of partitions contained in a column of an inch 

 in length appeared, upon a careful examination, to be 150; 

 and this number in a given length of column appears to be 

 common to all sizes, in the same state of humidity, for by 

 drying they may be greatly altered ; whence it appears pro- 

 bable, that the increase in the length of a column during the 

 growth of the animal does not enlarge the distance between 

 each partition, but that new partitions are formed, and added 

 to the extremity of each column. 



The partitions are very vascular; the arteries are branches 



