Chap. II. CONSTRUCTION OF THEIR BURROWS. Ill 



generally, or as I believe invariably, lined 



with a thin layer of fine, dark-coloured earth 



voided by the worms ; so that they must 



at first be made a little wider than their 



ultimate diameter. I have seen several 



burrows in undisturbed sand thus lined at 



a depth of 4 ft. 6 in. ; and others close 



to the surface thus lined in recently dug 



ground. The walls of fresh burrows are 



often dotted with little globular pellets of 



voided earth, still soft and viscid ; and these, 



as it appears, are spread out on all sides by 



the worm as it travels up or down its burrow. 



The lining thus formed becomes very com 



pact and smooth when nearly dry, and 



closely fits the worm's body. The minute 



reflexed bristles which project in rows on 



all sides from the body, thus have excellent 



points of support ; and the burrow is rendered 



well adapted for the rapid movement of the 



animal. The lining appears also to strengthen 



the walls, and perhaps saves the worm's body 



from being scratched. I think so because 



several burrows which passed through a layer 



of sifted coal-cinders, spread over turf to a 



thickness of 1^ inch, had been thus lined to an 

 6 



