Worms. 73 



its body and pushes its sharply pointed head into the 

 mass of soil which it is about to perforate, then having 

 insinuated the few foremost rings of its body into the 

 mould, the whole animal contracts in length, thus 

 swelling the front of the body in thickness and for- 

 cibly dilating the opening made by its fore part, 

 the worm being prevented by its hooks from slipping 

 out of the opening ; then it again lengthens its body 

 in front, its hooks giving it a fixed point from which 

 to act, and by a succession of such elongations and 

 thickenings it can ' worm ' its way through even a 

 hard gravel walk. 



The mouth of an earthworm is placed on the 

 second segment, near the apex of the body, and from 

 it the digestive canal extends as a straight tube through 

 the body. This tube is very wide and is always found 

 full of earth, as these animals devour large quantities 

 of the soil for the sake of the organic particles con- 

 tained in it, the remaining part being passed out, and 

 heaped by the worms at the outlet of their burrows, 

 as * wonn casts.' For the better division of the mate- 

 rial swallowed, the digestive canal is provided with a 

 muscular gizzard about fifteen rings behind its mouth. 

 The eggs in earthworms are produced in the 

 body cavity beginning at a point about seven rings 

 rom the mouth, and they usually fill the body for 

 ibout seven segments, distending it and producing a 

 thick white band or ring which we often notice in the 

 body of worms during early autumn. Worms are 

 propagated exclusively by eggs, the common belief 

 that, when cut in pieces, each part is capable of inde- 

 pend'.nt life not being strictly true. If we divide an 



