Chap. II. EJECTION OF THEIR CASTINGS. 119 



When a worm comes to the surface to eject 

 earth, the tail protrudes, but when it collects 

 leaves its head must protrude. Worms there- 

 fore must have the power of turning round 

 in their closely-fitting burrows ; and this, as 

 it appears to us, would be a difficult feat. As 

 soon as a little heap has been 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. 



Worms do not always eject their castings on 



