THE LIVER FLUKE 133 



(3) Place the animal on a slide and put a cover glass 

 over it in order to flatten it. Back of the middle portion 

 look for a cylindrical muscular body. This is the pharynx, 

 which connects with the mouth by a very short esophagus. 

 The pharynx can be protruded through the mouth. Do you 

 find a digestive tract leading from the pharynx? Trace it 

 to the anterior and posterior parts of the body. How 

 many main pouches has it? Has it an opening to the ex- 

 terior? How does it get rid of indigestible food material? 



(4) This peculiar arrangement of the alimentary tract 

 suggested the name of the order, Triclada, to which Pla- 

 naria belong. What does the word mean? Draw, showing 

 points mentioned (XS)- 



(5) Look underneath the eyespots for a light-colored 

 ganglionic mass, the brain. How many parts to it? Are 

 there nerve cords arising from it? How many? Draw. 



(6) With the high power examine the margin of the 

 animal for cilia. Do you find any? 



(7) Cut a Planarian in two and place the two pieces in 

 a tumbler of water. Examine every day, and note what 

 becomes of them. 



Planaria belong to the class Turbellaria. 



THE LIVER FLUKE 



Suggestions for Collecting. — (i) The Liver Fluke, 

 Distomum, inhabits the larger bile ducts of the sheep, 

 where it lives upon the biliary matter. This part of the 

 sheep's liver may be obtained from the slaughter house, 

 the bile ducts opened and the contents scraped out into 



