THi; ELECTRICAL ORGANS. 



5S 



npper and under surfaces of the body ; posterior in Oymno- 

 tus, and anterior in Malapterunis, tlie laraellse being disposed 

 perpendicularly to tlie axis in these two fishes. And this sur- 

 face, when the discharge takes place, is always negative to 

 the other. 



Fio 18. — The Torpedo, with Us electiical apnsratus displayed. — ^, branchia; ; c. brain * t 

 electric organ ; ly, cranium; me, spinal cord; 7t, nerves to the pectoral fliis; n/, iwni 

 later (Lies ; np^ brandies of the pneuiuogastric nerves ^oing to the electric organ ■ o, 

 eye. ° ' 



In Torpedo the nerves of the electrical organs proceed 

 from the fifth pair, and from the " electric lobe " of the 

 medulla oblongata, which appears to be developed at the 

 origin of the pneumogastrics. In the other electrical fishes 

 the organs are supplied by spinal nerves ; and, in Malapte- 

 rurus, the nerve consists of a single gigantic primitive fibre, 

 which subdivides in the electrical organ. 



The ordinary Rays possess organs of much the same 

 structure as the electrical apparatus, at the sides of the tail. 



The Nervous System: the Micephalon. — In all verte- 

 brated animals except AmpMoxits, the brain exhibits that 

 separation into a, fore-bralii^mid-hrain^z.-aA. hind-brain, which 



