Worms. 73 



beginning to burrow, the worrh lengthens 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, its muscular pharynx 

 is driven forward, thus swelling the front of the body 

 in thickness and forcibly dilating the opening made 

 by its fore part, the worm being prevented by its 

 bristles from slipping out of the opening; then it again 

 lengthens its body in front, its setae 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 is placed on the second segment, the 

 first being a cephalic lobe or lip, and from it the 

 wide digestive canal extends as a straight tube 

 through the body. This tube is always found full 

 of earth, which is devoured in large quantities for 

 the sake of the organic particles contained in it, 

 the remaining part being passed out and heaped by 

 the worms at the outlet of their burrows, as ' worm 

 casts/ For the better division of the material swal- 

 lowed, the digestive canal is provided with a muscular 

 gizzard about eighteen rings behind its mouth. 



The eggs in earthworms are produced in two small 

 ovaries in the thirteenth ring and opening on the 

 fourteenth ring. The twenty-sixth to the thirty-second 

 ring in adult worms are white and swollen from the 

 lar^e development of cutaneous glands. Worms are 

 propagated exclusively by eggs, the common belief, 

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

 pendent life ; not being strictly true. If we divide an 



