WILD LIFE OF ORCHARD AND FIELD 



an appearance of listless enjoyment when they 

 hang down, and an immense alertness if they are 

 rigid, as happens when the snail is on a march. 



The eyes at the extremity of the stalks are well 

 formed, though covered by a pellicle of skin. Of 

 how much practical use they are seems a matter 

 of doubt, Binney, Lubbock, and other authorities 

 making little of their usefulness. Dr. James Weir, 

 in his Dawn of Reason, on the other hand, re- 

 gards them as of decided service to the animal. 

 ''Actual experimentation,'' he says, ''declares 

 that the garden snail can see a moving white ob- 

 ject, such as a moving ball of cotton or twine,, at a 

 distance of two feet. In my experiments I used a 

 pole ten feet in length, from the tip of which a white 

 or dark ball was suspended by a string. The ball 

 was made to describe a pendulum - like movement 

 to and fro in front of the snail on a level with the 

 tips of its horns. Time and again I have seen a 

 snail draw in its horns when it perceived the white 

 ball, to it an unknown and terror-inspiring object. 

 I have likewise seen it change its line of march, 

 and proceed in another direction, in order to avoid 

 the mysterious white stranger dancing athwart its 

 pathway. Dark-colored objects are not so readily 

 perceived. . . . Sometimes it will not perceive the 



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