OF THE BRITISH ISLANDS. 



"5 



No. 216, are occasionally taken in British waters, their head- 

 quarters being the Mediterranean and tropical seas. The 

 remarkable feature concerning these fish is their possession 

 of a complex electrical apparatus. This apparatus, 

 which is developed in equal proportions on each side of 

 the anterior region of the body, consists, as described by 

 Professor Huxley ('Anatomy of Vertebrated Animals'), "of 

 nearly parallel lamellae of connective tissue, enclosing small 

 chambers, in which lie what are termed the electrical plates. 

 These are cellular structures, on one face of which the final 



FIG. 29. — torpedo (Torpedo hebetans). 



ramifications of the nerves that supply the electrical organs 

 are distributed. In the 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 deve- 

 loped at the origin of the pneumogastric." When laid open 

 with the dissecting knife this electrical apparatus presents 

 to the ordinary observer much the appearance of a honey- 

 comb, being composed, as viewed from above, of numer- 

 ous perpendicularly-set hexagonal compartments, the wax 

 walls of the honeycomb being represented by a gelatinous 

 membrane of extreme tenuity, and containing within them 



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