136 WORMS 



several days in common water to which a little white of 

 has been added. 



(2) Examine the Tapeworm for dorsal and ventral 

 sides ; anterior and posterior ends. Has it any color ? If 

 not, why? 



(3) Examine the head (Scolex). Do you find anything 

 by which it may attach itself to the intestinal wall? What 

 is the nature of the attaching organ ? Do you find a mouth ? 

 Has it an alimentary tract? If not, how does it secure its 

 food? Has it organs of locomotion? Does it need any? 

 Is the worm segmented? Each division is called a pro- 

 glottid. Are the proglottids all alike in shape and size? 

 Can a proglottid live free from the rest of the animal? 

 Try it. 



(4) Just back of the scolex is the neck. Is it segmented ? 

 Trace a worm from the head backward, noting differences 

 in segmentation and size of proglottids. 



In what respects is the Tapeworm like Planaria and Dis- 

 tomum ? How does it differ ? 



Tapeworms belong to the order Cestoda. 



Note. — Both Trematoda and Cestoda have interesting life his- 

 tories which should receive considerable attention on account of 

 economic and medicinal reasons. 



Classification. — The following table will give an idea of the 

 relationships of the common animals of this branch. 



1. Class Platyhelminthes. 



1. Turbellaria. Planaria. 



2. Trematoda. Fluke. 



3. Cestoda. Tapeworm. 



2. Class Nemathelminthes. 



1. Nematoda. Trichina. 



2. Acanthocephala. Hook-headed worms, parasites. 



