PECULIAR SECRETIONS. 369 



they consisted of perpendicular hollow columns, reaching 

 from the ventral to the dorsal surface of the animal ; and, 

 where the organ is thickest, extending to an inch and a 

 half in length ; and where thinnest, to one-fourth of an 

 inch. These columns he found to be four, five, and even 

 six-sided ; but Mr Tod is inclined to consider them cylindri- 

 cal*. The coats of the columns are thin and transparent, 

 closely connected with each other, by a loose network of ten- 

 dinous fibres, passing transversely and obliquely between 

 the columns. They are, likewise, attached by strong ine- 

 lastic fibres, which pass directly from one column to ano- 

 ther. The cavity of each column is divided into a num- 

 ber of cells, (containing a fluid which M. GEOFFROY found 

 composed of albumen and gelatine), by transverse partitions, 

 which, in a column of one inch, amount to 150. These 

 partitions consist of a very thin translucent membrane ; 

 their edges appear to be attached to one another, and they 

 are connected to the inside of the columns by a fine cellu- 

 lar membrane. The whole organ is covered by a thin mem- 

 brane, composed of fibres running in a longitudinal direc- 

 tion, and united to the skin, or surrounding parts of the 

 body, by a cellular substance. Within this external mem- 

 brane of the electrical organ, there is another, consisting 

 likewise of fibres, running, however, in a transverse direc- 

 tion. The sides of the columns take their rise from this 

 membrane. The arteries by which the electrical organs are 

 nourished, after penetrating the investing membrane, ra- 

 mify upon the sides of the columns, and send in, to the 

 partitions, numerous small branches, which anastomose with 

 one another, and with the vessels of the adjacent partitions. 



* Phil. Trans. 1816, p. 121. 



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