298 ELECTRICAL ORGANS IN FISHES. 



oblongata, and consists of a large lobe on each side of its an- 

 terior part. Valentin (" Electricitat der Thiere," in Wagner's 

 Handworterh) states that these lobes consist of nucleated 

 cellules so large as to be visible to the naked eye. The an- 

 terior or trigeminal electrical nerve is derived from the non- 

 ganglionic portion of the third division of the fifth ; the three 

 posterior or vagal electrical nerves pass out along with the 

 branchial divisions of the eighth nerve, but have no connec- 

 tion with the ganglionic masses developed on the branchial 

 nerves. These electrical nerves belong, therefore, to the non- 

 ganglionic series, with central relations similar to those of 

 motor nerves. 



The batteries of Gymnotus are supplied by about 224 pairs 

 of nerves (J. Hunter, Phil. Trans. 1775 ; Eudolphi, Alhand. 

 der K. Akad. zu Berlin, 1820) on each side. These are all 

 derived from the inferior or motor roots of the spinal nerves ; 

 none being supplied by the lateral nerve, or combined branch 

 of the fifth and eighth. The spinal cord exhibits no peculiar 

 development, nor indication of the existence in it of a series 

 of electrical nervous centres ; but Valentin (Wagner's Hand- 

 loorterh. loc-cit. 1842) has described a great lobe springing 

 from each side of the brain between the peduncle of the 

 cerebellum and the mesocephalon, extending upwards and 

 forwards with its fellow of the opposite side, like an anterior 

 or supplementary cerebellum. These lobes, according to 

 Valentin, exhibit no trace of the large characteristic nucleated 

 cells which exist in the electrical lobes of Torpedo. Whether 

 the electrical lobes in Gymnotus be peculiar developments of 

 the cerebellum, or of the grey matter at the cerebral ex- 

 tremities of the motor columns of the spinal cord, they present 

 a highly interesting arrangement. 



The presumed deep electrical layer of INIalapterurus, which 

 is merely a fatty mass, is supplied by branches of the spinal 

 nerves ; but the true electrical organs or batteries are supplied, 



