ADAPTATION FOR PROTECTION FROM ENEMIES 99 

 E. Defensive Structures 

 Another Method of Protection from Enemies 



Materials. 



Specimens, charts, books, etc., to illustrate the various 

 defensive organs found among invertebrates. 



Observations and questions. 



1. Describe the stinging hairs of the paramaecium. 



2. Describe the action and structure of nettle cells. 

 Where are they located in the case of hydra ; of jellyfish ? 



3. What defensive organs are found among the 

 arthropods ? 



4. What are stinkbugs.' What peculiar organs of de- 

 fense have the caterpillars of the swallowtail butterflies } 



5. Where is the sting of a hornet located .? To what in 

 a grasshopper does it correspond .■' Why does a hornet or 

 bee inflict so painful a wound .-' 



6. What peculiar organ of defense has a squid .' 



7. Find other examples of defensive structures. 



Summary. 



1. What advantages have organs of defense as a method 

 of protection ? 



2. What disadvantages .' 



F. Thesis 



To sum up the Important Points in the Study of Adapta- 

 tions for Protection 

 Directions. 



Write a connected account of what you have found out 

 about protection of animals from their enemies, using the 

 following outline : — 



