Chap. II. PROTECTION OF THEIE BUEEOWS. 63 



radiation at night, from the surrounding 

 ground and herbage. I am inclined to be- 

 lieve in tbis latter view ; firstly, because when 

 worms were kept in pots in a room with a 

 fire, in which case cold air could not enter the 

 burrows, they plugged them up in a slovenly 

 manner ; and secondarily, because they often 

 coat the upper part of their burrows with 

 leaves, apparently to prevent their bodies from 

 coming into close contact with the cold damp 

 earth. But the plugging-up process may 

 perhaps serve for all the above purposes. 



Whatever the motive may be, it appears 

 that worms much dislike leaving the mouths 

 of their burrows open. Nevertheless they 

 will reopen them at night, whether or not 

 they can afterwards close them. Numerous 

 open burrows may be seen on recently-dug 

 ground, for in this case the worms eject their 

 castings in cavities left in the ground, or in 

 the old burrows, instead of piling them over 

 the mouths of their burrows, and they cannot 

 collect objects on the surface by which tho 

 mouths might be protected. So again on a 

 recently disinterred pavement of a Roman 

 villa at Abinger (hereafter to be described > 



