mentary spell of nervousness once more began to 

 garb himself, but this time entirely in vegetation 

 of green. 



In truth, except for a seeming indifference to 

 black, the spider-crab can distinguish all hues ; for 

 (as I later found in my experiments with these 

 creatures) with the exception just noted, regard- 

 less of the color of their environment — red, green, 

 blue, brown or orange — they unerringly select 

 materials at their disposal, whether it be paper 

 rags or plants, which will more nearly match. 



Moreover, in a tank evenly divided in halves of 

 a different color such as red and green, crabs 

 already clothed in one or the other of the corre- 

 sponding colors when transferred to this aquarium 

 will make their way toward the region harmonizing 

 with the hue of their coat. That is to say, the red 

 crabs seek the red end of a red-green tank while 

 the green crabs move toward the green. 



But here arises a surprising thing, if we con- 

 sider the foregoing results of experiment as a 

 striking manifestation of a marvelous instinct: A 

 red crab when put into a green aquarium will not 

 rid itself of its conspicuous panoply, nor, like- 

 wise, will a green crab when placed in surround- 



[238] 



