Chap. II. EJECTION OF THEIR CASTINGS. 117 



As soon as a little heap is formed, the 

 worm apparently avoids, for the sake of 

 safety, protruding its tail; and the earthy 

 matter is forced up through the previously 

 deposited soft mass. The mouth of the same 

 burrow is used for this purpose for a consider- 

 able time. In the case of the tower-like 

 castings (see Fig. 2) near Nice, and of the 

 similar but still taller towers from Bengal 

 (hereafter to be described and figured) a 

 considerable degree of skill is exhibited in 

 their construction. Dr. King also observed 

 that the passage up these towers hardly ever 

 ran in the same exact line with the under- 

 lying burrow, so that a thin cylindrical object 

 such as a haulm of grass, could not be 

 passed down the tower into the burrow ; and 

 this change of direction probably serves in 

 some manner as a protection. When a w^orm 

 comes to the surface to eject earth, the tail 

 protrudes, but when it collects leaves its head 

 must protrude. Worms therefore must have 

 the power of turning round in their closely- 

 fitting burrows ; and this, as it appears to us, 

 would be a difficult feat. 



Worms do not always eject their castings on 



