COMMISSION OF ERROR 521 



an American correspondent of * Nature ' tells us that the 

 common frog in the United States utters a particular cry, 

 when alarmed by its enemy, the striped snake (tropidonotus 

 tama, Dakay), and that ' sliding a stick after him, like a 

 snake, will produce the same result, in a still more striking 

 manner.' 



Dr. Brown, speaking of the grampus, of Greenland, says, 

 * I know of a case in which they attacked a white-painted 

 herring boat, in the Western Islands, probably mistaking it 

 for a beluga,' or white whale. 



The kitten is said to play with shadows, even its own, on 

 the wall, mistaking them apparently for living, moving, but 

 harmless realities. The celebrated French traveller, Le 

 Vaillant, mentions a young monkey mistaking a wig Hock 

 for its mother. The dog is sometimes deceived by false or 

 imitation fire. Dance describes something of an opposite 

 kind in a toad. He speaks of an Indian peon, in Venezuela, 

 ' throwing live coals to a toad, which jumped forward at each 

 throw, and caught the bright coals in its mouth, dropping 

 one to take up another. The toad must have mistaken 

 the coals for fire flies, and it was not deterred from hoping 

 for better luck at each succeeding trial.' 



The protective disguises of various plants and animals lead 

 other animals into errors of non-observation, or faulty obser- 

 vation. Many seeds or seed-vessels, various insects, even 

 huge animals such as the crocodile and alligator, are externally 

 so like certain natural objects of an unattractive kind for food 

 purposes, that they escape, or repulse the notice even of 

 keen-eyed predatory birds. 



Bates and Wallace, in particular, have shown how fre- 

 quently, by means of what are called their mimetic resemblances, 

 in colour or form, to the ground or grass, tree-barks, leaves, 

 or twigs, certain insects secure immunity from their 

 natural enemies birds of various kinds. Many phasmata 

 and mantides so resemble dry sticks as to be unrecognisable 

 by man even when he is on the outlook for them unless 

 they are in motion : as I found for myself in the New Zea- 

 land Bush many years ago. The leaf insect, so well described 

 and figured by the late Andrew Murray, F.L.S., one of our 



