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such organ occurs in its congener. Polynenius paradiseus is 

 without, but all the others of the genus have one ; in the 

 sebastes it is very large, but in the next genus scarcely the 

 size of a pea. Some conjectural inferences on the modification 

 of the manners and character of the species resulting from the 

 possession or the privation of this organ, may however be 

 offered, such as we have already produced, and may again 

 refer to in the particular reviews of the greater sections or 

 families of this class. 



The electrical shocks which it is in the power of some 

 species of fish to give other bodies, present another striking 

 singularity in their structure, particularly as the organs used 

 for that purpose are no less different among them than they 

 differ from all other species of organs. In torpedos the 

 apparatus consists of membranous tubes, filled with mucosity, 

 and divided by transverse partitions closely pressed together, 

 like honey-combs ; it is placed on each side of the head, and 

 provided with enormous branches of nerves from the fifth and 

 eighth pair. In gymnoti the whole of the under part of the 

 body is densely furnished with parallel laminae, separated by 

 thin layers of mucilage. In silurus two layers of different 

 substances are interposed between the skin and the muscles, 

 over the greater part of the body, the exterior of which is 

 cellulous and aponeurotic on the internal surface, receiving 

 nerves from the fifth pair ; and the interior layer is of a 

 flocculent texture, deriving nerves from the intercostals. By 

 means of these organs, where, on account of the alternation 

 of different laminae, analogy has been considered to exist with 

 a galvanic pile, the animals can give or withhold at will, 

 shocks truly electrical to those who touch or only approach 

 them ; they are to them a powerful instrument of defence, 

 and serve probably also to stun their prey. 



Organs of generation. The rays, sharks, and chimaeras, 

 who produce large roes or eggs, protected by strong horny 



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