104 EARTHWORM 



An Earthworm's Work. — After a rainy day our paths and 

 lawns are often almost covered with little heaj^s of dirt that 

 earthworms have cast up from their holes. The earth thrown 

 out during the summer is enough to cover the ground nearly 

 a quarter of an inch deep. Thus worms plow the soil for the 

 farmer and enrich it by burying grass and bones and every- 

 thing else that lies on the ground. They loosen the soil to a 

 greater depth than man can reach with his plow, and they 

 open ways for plants to reach down many feet through soils 

 too firm for their roots alone to pierce. 



How Earthworms travel. — As you hold an earthworm with 

 one hand and gently pass the thumb and forefinger of the 

 other hand along its body, you may feel two rows of little 

 spines. In order to feel them the more plainly, which way 

 must you pass your fingers, toward its head or toward its tail? 

 These spines are a kind of feet. A worm travels up and down 

 its smooth tunnel by thrusting forward the front half of its 

 body and holding by its spines while it draws up the hinder 

 half. 



An Earthworm's Blood. — If a large earthworm is kept warm 

 and moist, you can plainly see the pulse beating in its blood tubes. 

 In which vein does the blood flow toward the head, in the one 

 on its back, or in the under one ? 



An earthworm breathes through its skin. If its skin be- 

 comes dry, the worm soon dies. Why ? 



