870 Dynamic Theory. 



stance. " " These crabs inhabit deep burrows which they hollow out be- 

 neath the roots of trees, and where they accumulate surprising quanti- 

 ties of the picked fibres of the cocoa-nut husk, on which they rest as on 

 a bed. The Malays sometimes take advantage of this, and collect the 

 fibrous mass to use as junk." (Darwin, Cruise of the Beagle, 492.) 



The species of these crabs called the Purse crab, is found on the Car- 

 oline Islands. It grows to from 18 to 24 inches long, and can raise it- 

 self to a hight of nearly a foot above ground. It climbs the cocoa-nut 

 tree, cuts off two or three nuts with its strong claws, and throws them 

 down. It pulls off the husks, and breaks open the nut like the crab 

 described above. But sometimes it breaks the nut by seizing it with its 

 big pincers and striking it against a stone. 



The skill and versatility of the Beaver are of a high order. The con- 

 struction of their works is adapted to the locality, and some of them 

 are very extensive, requiring the co-operation of many workmen for a * 

 long time. The liability of their dams to accident from floods, requires 

 their knowledge of l^draulics to be adaptive, as no two cases are pre- 

 cisely alike. Their skill in working out the details of a dam, are often 

 entirely human. They will cut down a tree a foot in diameter, cutting 

 in such a way as to cause it to fall across the stream. Then they will 

 cut enough stout sticks to make a slanting floor when laid side by side, 

 reaching from one side of the stream to the other, one end of each 

 stick resting on the large cross-log. Then they will cover the slanting 

 floor with grass, leaves and earth to make it water-tight. If a break oc- 

 curs they do not lose their heads but know just how to stop it up. 



The ape tribes are, next to man, the most intelligent. They possess 

 a great faculty for imitation, and a desire to do what they see other 

 folks do. Imitation is an exceedingly human faculty, the greater part 

 of our actions and ideas being copied by the rising generation from the 

 retiring one. But the ape is also liable to those new original ideas 

 which arise by the breaking up and reconstruction of old ones in the 

 cerebrum. An orang is mentioned that learned how to open his cage 

 door by turning the key or latch. He reached it by means of a sus- 

 pended rope to which he clung. His keeper tied knots in the rope so 

 as to make it too short for his purpose, and then he climbed the rope 

 above the knots and untied them. When presented with a bunch of keys, 

 he tried them one after another to unlock the door he wanted to open. 



The following anecdotes prove the possession, by different animals, 

 of such reasoning powers as are competent to work out purposive ac- 

 tions, just as they are worked but in a human brain. 



Wm. Livesay, in Jefferson Co., 111., many years ago was much 

 troubled by crows, which as soon as his corn was up, swarmed down 

 into his clearing, and guided by the tender spears just visible above the 



