Page:Natural History, Fishes.djvu/81

Rh 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 is golden. The lateral line is distinct, running in a slightly arching line from the gill-flap to the tail-fin.

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. Speaking of these fishes, he says, "There is certainly a very extraordinary phenomenon attending them, the cause of which I leave to naturalists to ascertain. 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 membrane, it is evident that some have been much longer in this state than others, yet there appears no difference 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;