ELECTRIC ORGANS. 



125 



side of the head (Fig. 100, E] ; in Gymnotus they lie in the 

 ventral portions of the enormously long tail (Fig. 101, E] that is, 

 in the position usually occupied by the ventral portions of the 

 great lateral muscles; and finally, in Malapterurus, the electric 

 organ extends between the skin and muscles round almost the 

 entire circumference of the body, thus enclosing the Fish like a 

 mantle : it is especially strongly developed along the sides. 



FIG. 101, A anil B. THE ELECTRIC ORGAN OF Gymnotus clectricus. (B, from a 



preparation by A. Ecker. ) 



H, skin ; Fl, fin ; DM, DM 1 , dorsal portions of the, great lateral muscles, seen partly 

 in transverse section, partly in longitudinal ; VM, VM 1 , ventral portions of 

 ditto ; E, the electric organ, seen in transverse section at J (B), and from the 

 side at E l ; Jl'S, vertebral column, from the side, showing the spinal nerves, 

 and }VS l , in transverse section ; LH, posterior end of" body-cavity ; Scp, 

 median longitudinal fibrous septum, which divides the electric oro-an and the 

 lateral trunk-muscles into two equal halves : A, anus. 



The electric power of those Fishes which were formerly known 

 as " pseudo-electric " has now been fully demonstrated, though it 

 is much feebler than in the forms described above. To this category 

 belong all the Rays, with the exception of Torpedo, the various 

 species of Mormyrus, and Gymnarchus (both belonging to the 

 Teleostei). In all these, the electric organs lie on either side 



