I'ERCH. 



been noticed by Linnaeus as occurring at Falilun, in Sweden, 

 and in other lakes in the North of Europe. Similar Perch 

 are also found in Llyn Raithlyn, in Merionethshire. A fish 

 of this description is figured in the volume of Daniefs Rural 

 Sports devoted to Fishing and Shooting, page 247. Speci- 

 mens of the Perch, almost entirely white, have also been 

 found in the waters of particular soils. 



Two Continental naturalists have pointed out the neces- 

 sity of attending to the scales of fishes, as affording the most 

 valuable and constant characters ; and these productions of 

 the skin, important also as the organs of protection and rela- 

 tion between the animal and the medium in which it resides, 

 will occasionally be figured and refen-ed to as additional 

 marks of specific distinction in several instances of closely 

 allied species. It has already been observed that the lateral 

 line in fishes marks the situation of an extended series of 

 mucous orifices. The scales placed in a row immediately 

 upon this lateral line mark its particular course along the 

 side ; and these scales, besides bearing the characters of those 

 of the other parts, are perforated by a tube through which 

 escapes this mucus, or slime, as it is more commonly called, 

 to be spread over the surface of the body. The vignette 

 below represents a scale from the lateral line of the Perch, 

 the Basse,^ and the Ruife.^ 



