THE PERCH FAMILY. 69 



in the case of the Pope united in the centre, thus forming a 

 single long fin slightly indented, whilst in the Perch they 

 form two entirely distinct fins. This peculiarity of the 

 double dorsal fin is confined amongst British fresh- water 

 fish exclusively to the Perch, to the Burbot, and to the 

 Salmon family. 



It is singular that the Ruffe, so nearly resembling the 

 Perch in most of its characteristics, should yet differ in 

 one so marked as the nature of the waters which it in- 

 habits ; but whilst the Perch lives indifferently in streams 

 and ponds, and apparently thrives equally well in both, 

 the Ruffe is never found, so far as I am aware, in other 

 than running water. Although, howevei', a purely river- 

 fish, and considered as by no means unpalatable food, 

 it is seldom sufficiently numerous in this country to be- 

 come an object of exclusive attention to the angler, but is 

 usually taken incidentally whilst in pursuit of other fish, 

 and more particularly when raking for Gudgeon, — the 

 small larvae and other insects turned up in this operation 

 possessing apparently an equal attraction for both species. 

 The Ruffe also, like the Gudgeon, is very easily tempted by 

 a red worm, which, if offered in judicious proximity to his 

 nose, he will rarely or never refuse. 



Prom its resemblance to the latter species in its colour- 

 ing, and to the Perch, as already pointed out, in form and 

 habits, the Ruffe has been considered by some authors to 

 be a hybrid between the two, — that is, to be produced from 

 the ova of the one vivified by the milt of the other : for 



