Specimens, charts, books, etc., to illustrate the various defensive organs found among invertebrates.

Observations and questions.
  1. Describe the stinging hairs of the paramecium.
  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 defense 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 Adaptations for Protection

Directions.

Write a connected account of what you have found out about protection of animals from their enemies, using the following outline:—

  1. The struggle for existence—
    1. its cause,
    2. its threefold nature,
    3. the various kinds of adaptations.
  2. The various methods of protection from enemies.
    1. The exoskeleton.
    2. Protective coloration.
    3. Animal associations.
    4. Protective habits.
    5. Defensive structures.