CHAP. VII. CONCLUSION. 315 



time they are accidentally uncovered and 

 germinate. 



Worms are poorly provided with sense- 

 organs, for they cannot be said to see, 

 although they can just distinguish between 

 light and darkness ; they are completely deaf, 

 and have only a feeble power of smell ; the 

 sense of touch alone is well developed. They 

 can therefore learn but little about the outside 

 world, and it is surprising that they should 

 exhibit some skill in lining their burrows 

 with their castings and with leaves, and in 

 the case of some species in piling up their 

 castings into tower-like constructions. But it 

 is far more surprising that they should ap- 

 parently exhibit some degree of intelligence 

 instead of a mere blind instinctive impulse, in 

 their manner of plugging up the mouths of 

 their burrows. They act in nearly the same 

 manner as would a man, who had to close a 

 cylindrical tube with different kinds of leaves, 

 petioles, triangles of paper, &c., for they 

 commonly seize such objects by their pointed 

 ends. But with thin objects a certain number 

 are drawn in by their broader ends. They do 

 not act in the same unvarying manner in all 



