110 HABITS OF WORMS. Chap. II. 



to a height of 2^ inches. The tallest of those 

 which were measured was 3*3 inches in height 

 and 1 inch in diameter. A small cylindrical 

 passage runs up the centre of each tower, 

 through which the worm ascends to eject the 

 earth which it has swallowed, and thus to 

 add to its height. A structure of this kind 

 would not allow leaves being easily dragged 

 from the surrounding ground into the bur- 

 rows ; and Dr. King, who looked carefully, 

 never saw even a fragment of a leaf thus 

 drawn in. Nor could any trace be discovered 

 of the worms having crawled down the ex- 

 terior surfaces of the towers in search of 

 leaves; and had they done so, tracks would 

 almost certainly have been left on the upper 

 part whilst it remained soft. It does not, 

 however, follow that these worms do not 

 draw leaves into their burrows during some 

 other season of the year, at which time they 

 would not build up their towers. 



From the several foregoing cases, it can 

 hardly be doubted that worms swallow earth, 

 not only for the sake of making their bur- 

 rows, but for obtaining food. Hensen, how- 

 ever, concludes from his analyses of mould 



