THE LEECH I3I 



a dissecting microscope. Notice the larger fleshy portion. 

 This is a branchia. What is it used for? On the dorsal 

 side of the branchia is a small projection called the dorsal 

 cirrus. Below the branchia are three sets of setae. What is 

 their use? Just below the last bunch of setae is another 

 cirrus called the ventral cirrus. Just beneath the ventral 

 parapodium may be seen the openings of the nephrida. 

 Draw (X4)- 



(2) Examine the anterior end of the body. Note the 

 prostomium. Does it project over the mouth? Notice the 

 slender projections from the front segment. These are 

 tentacles. How many pairs ? What is their function ? Note 

 the two fleshy projections. These are palpi. 



(3) Do you find eyesf How many? Where are they? 

 Slit the worm open, beginning at the head, for seven or 

 eight segments. Note the large proboscis. This is now 

 folded in. It may be rolled inside out like the fingers of 

 a glove. Do this and note the two powerful jaws. Does 

 this suggest its kind of food? What is its food? Draw 

 proboscis showing all the parts. 



THE LEECH 



Leeches live in water. They may be found on the under- 

 side of old boards, rocks or other objects near the edges of 

 ponds and ditches. 



(i) Examine a live leech. Note color. Is the color 

 the same all over the body? 



(2) Has it organs of locomotion? Place one in water. 



