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XV. THE FA]\IILY OF THE SILURID^. 



This family is entitled on many accounts to take 

 the lead in the order, as assigned to it by M.Valen- 

 ciennes. Its fins are more osseous than those of any 

 other family of the soft-finned division. Besides, 

 the number of its species is very great, about three 

 hundred having been already catalogued ; and it is 

 one of the most curious in the class Yertebratce, on 

 account of the variety of organization it presents, 

 \vhether compared with other fishes, or the dif- 

 ferent members of the family among themselves. 

 The Siluridas generally inhabit rivers, and other 

 fresh- water resorts, over the greater part of the 

 world; and they sometimes wander to the ocean. By 

 much the greater number live in equatorial latitudes ; 

 but they are able to support the rigour of a north- 

 em climate, or great heights on mountain ranges ; 

 and hence some of the family are found on the con- 

 tinent of South America, at elevations between 

 10,000 and 16,000 feet above the level of the sea; 

 and they also, according to the observation of M. de 

 Humboldt, penetrate into the interior of the earth, 

 and exhibit to the physiologist new phases of the 

 vital principle in the interior lakes of those gigantic 

 American volcanoes which throw forth fish in the 

 course of their eruptions. It is somewhat remark- 



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