Chap. 11. 'J'HEIB INTELLIGENCE. 71 



are regularly drawn into the mouths of worm- 

 burrows. Tliese leaves consist of two needles, 

 which are of considerable length in the two 

 first and short in the last named species, and 

 are united to a common base ; and it is by this 

 part that they are almost invariably drawn 

 into the burrows. I have seen only two or 

 at most three exceptions to this rule with 

 worms in a state of nature. As the- sharply 

 pointed needles diverge a little, and as several 

 leaves are drawn into the same burrow, each 

 tuft forms a perfect chevaux de frise. On two 

 occasions many of these tufts were pulled up 

 in the evening, but by the following morning 

 fresh leaves had been pulled in, and the 

 burrows were again well protected. These 

 leaves could not be dragged into the burrows 

 to any depth, except by their bases, as a 

 worm cannot seize hold of the two needles at 

 the same time, and if one alone were seized 

 by the apex, the other would be pressed 

 against the ground and would resist the 

 entry of the seized one. This was manifest 

 in the above mentioned two or three excep- 

 tional cases. In order, therefore that worms 

 should do their work well, they must drag 



