154 FIRST BOOK OF ZOOLOGY. 



The most accessible worm is the common earthworm. 

 Specimens can be collected by digging for them in damp 

 earth ; and they may be found under almost any board or 

 rock which has lain for some time. 



The worms may be washed by placing them in a bowl 

 of water, where their movements will soon remove the 

 dirt. 



The body is composed of a series of rings or segments, 

 which are alike in form, except those at the extremities, 

 which differ. The body tapers at both ends. The forward 

 or anterior end tapers to a blunt point, while the hinder 

 end becomes broad and flattened. 



By carefully watching the worm when it shortens up 

 after a long stretch, there will be seen, projecting from the 

 sides and lower portion of each ring, minute points, which are 

 the ends of little bristles protruding from openings in the 

 sides. These bristles as they move project backward. 



FIG. 142. COMMON EARTHWOKM. 



The worm moves along the ground by the aid of these 

 bristles, or setce, as they are called. The body alternately 

 lengthens and shortens. When the body lengthens, the setae 



