PERCHES. 
67 
nearly the same hues as the parts from which they 
respectively arise ; but the caudal, the anal, and 
the ventrals have their rays of the most brilliant 
scarlet, especially the latter, and the membranes are 
[ tinged with the same hue. The iris of the eye 
j is golden. The lateral line is distinct, running 
i in a slightly arching line from the gill-flap to the 
I tail-fln. 
j Mr. Yarrell mentions, as having been found in 
' the waters of particular soils, specimens of the 
Perch almost entirely white ; and others of an 
uniform slate-grey hue with a silvery appearance. 
The latter variety is obtained in the ponds of 
Ravenfield Park, in Yorkshire, and is found to 
retain its peculiarity of colour, when transferred 
from its native ponds to other waters. 
Yet another variation of hue, associated with 
another curious peculiarity, is ascribed to the 
Perch of Malham, or Maum Tarn, in Yorkshire, 
by Hartley, the author of an account of some 
natural curiosities of that neighbourhood. Speak- 
ing of these Ashes, he says, There is certainly 
a very extraordinary phenomenon attending them, 
the cause of which I leave to naturalists to ascer- 
tain. After a certain age they become blind : a 
hard, thick, yellow film covers the whole surface 
of the eye, and renders the sight totally obscured. 
When this is the case, the fish generally are 
exceedingly black ; and although, from the more 
extreme toughness and consistency of the mem- 
brane, it is evident that some have been much 
longer in this state than others, yet there appears 
no difierence either in their flavour or condition. 
Perch of five pounds’ weight and more have been 
taken. They are only to be caught with a net ; 
