ROUND EYES DETECT MOTION, NOT FOEM. 27 



erally taken by the angler while they are foraging for food. 

 When salmon or trout rise to feed, they may always be taken 

 with a well-made artificial fly, presented to them gently and 

 artistically. 



The form of the eyes of almost all fishes proves them to be 

 near-sighted. All animals with very convex eyes quickly de- 

 tect the slightest motion, but lack the power to discriminate 

 form. Hence a deer, with its full lustrous eye, will approach 

 any still form to within a few feet of it, but at the first move- 

 ment it bounds away like the wind. In addition to the eyes 

 of fishes being convex, the density of the water as a medium 

 through which they see rather shortens than extends vision. 

 " The vision must also be farther limited from the eye being 

 covered with the common skin of the head to protect the eye- 

 ball ; and as they have no eyelids, of course the eyes never 

 close ; and, whether sleeping or waking, their vision must be 

 indistinct." White, of Selborne, states that eyes of fishes are 

 immovable ; but it is known that those of the silver and gold 

 fishes in glass cases turn in their sockets as occasion requires, 

 and that, while they take little notice of a lighted candle, they 

 will dart and appear much terrified if their glass house is 

 touched. As fishes have no eyelids, it is difficult to discern 

 the difference between their sleeping and waking hours. 

 That they do not always sleep in the night is proven by the 

 many instances when trout have been taken by rising to the 

 artificial white miller in total darkness. M. de Blainville at- 

 tributes the greatest distinctness of vision to migratory fishes, 

 because he states their eyes are the largest ; but, instead of 

 that being so, the cod is about the only migratory fish which 

 has larger eyes than the general run of river fishes, while 

 those with eyes of moderate size, such as the genus Pcrca and 

 those of the Salmo genus, give indications of better sight than 

 most sea fishes. Anglers of great experience and acknowl- 

 edged judgment select baits, whether live minnows, or such 

 artificial lures as flies, squids, etc., which contrast strongly 

 with the water and the color of the clouds. What angler 



