CH0NDR0PTERYGI1. 645 



on each side of the cranium and gills, reaching from thence 

 to the semicircular cartilages of each great fin, and extending 

 longitudinally from the anterior extremity of the animal to the 

 transverse cartilage which divides the thorax from the abdo- 

 men, and between these limits they occupy the whole space 

 between the skin of the upper and lower surfaces. They are 

 thickest at the edges, near the centre of the fish, and be- 

 come gradually thinner toward the extremities. Each organ 

 is attached to the surrounding parts by a close cellular mem- 

 brane, and also by short and strong tendinous fibres, which 

 pass directly across from its outer edge to the semicircular 

 cartilages. 



They are covered above and below by the common skin of 

 the animal, under which there is a thin fascia spread over 

 the whole organ. This is composed of fibres running in the 

 direction of the body of the animal : these fibres appear to 

 be perforated in innumerable places, which gives the fascia 

 the appearance of being fasciculated; its edges all round 

 are closely connected to the skin, and at last appear to be 

 lost, or to degenerate into the common cellular membrane of 

 the skin. 



Immediately under this is another membrane, exactly of 

 the same kind, the fibres of which in some measure decussate 

 those of the former, passing from the middle line of the body 

 outward and backward. This inner fascia appears to be conti- 

 nued into the electric organ by so many processes, and 

 thereby makes the membranous sides or sheaths of the co- 

 lumns, presently to be described. 



Each organ consists wholly of perpendicular columns, 

 reaching from the upper to the under surface of the body, 

 and varying in their lengths according to the thickness of the 

 parts of the body where they are placed. The figures of 

 these columns are very irregular, varying according to situa- 



