'126 WORMS 



(2) Note its color. Is it the same on both sides ? Notice 

 a streak of red in the mid-dorsal line. This is the dorsal 

 blood vessel showing through the body wall. Can you see 

 blood moving in it? In what direction? Look on the 

 ventral side for a similar red line, the ventral blood vessel. 



(3) Has it eyes? Where? Can it feel? Hear? Con- 

 sult reference books to answer these questions. 



(4) Note the circular rings which make up the entire 

 body. Count them. Are they all the same size? Each 

 ring is called a segment or annulus. 



(5) Notice the thick white girdle, the clitellum, near the 

 anterior end. How many segments is it from the front end ? 

 This is connected with reproduction. Is it in the same 

 position in all worms? Sketch the entire worm. 



(6) Kill a worm in chloroform. Strip off the outer 

 skin, or the cuticle, and examine with the microscope. Note 

 markings and thickenings. Sketch. 



(7) Place a live worm on a piece of paper and watch its 

 movements. Draw it backward, ventral side down, over the 

 finger. Is there any resistance? With a dissecting micro- 

 scope look for spines. Where are they located ? How many 

 rows? Are they in each segment? These are called setae 

 (sing., seta). Can you now determine how the animal 

 moves ? Boil a piece of the body wall of an alcoholic speci- 

 men in caustic potash to free the setae. Wash in water. 

 The setae will fall to the bottom. Pour off the water and 

 mount some of the residue in glycerine or balsam for study. 

 Draw. 



(8) Look for the mouth. Where is it? In front of 

 the mouth note a projection, the prostomiuin. Look for 

 the anus. Where is it? Look for two slitlike openings in 



