Understand its habitat and with what forms it is usually associated.

  1. Observe the free-swimming movements of the organism, and the englenoid changes in the foim of the body Make drawings showing the changes in the shape of a single in-di vklual
  2. Distinguish anterior and posterior ends. Is there any dorsoventral differentiation? Note the motile organ, the flagellum. Where is it attached? What relation does it bear to the gullet? How is it directed during locomotion of the organism Does it serve any other purpose besides locomotion?
  3. The green color of Euglena is due to chlorophyll, and this enables the animal to live in the clearest water, being nourished like a typical green plant, but minute particles of food are also taken into the endoplasm through the gullet, and thus Euglena combines holozoic and halophytic methods of nutrition Consider the bearing of this on the position of Euglena and its allies in the protozoan scale
  4. Note the absence of color near the anterior and posterior ends of the organism. Near the anterior end alao notice the red pigment spot, or stigma. What is its probable function?
  5. Stain a specimen with iodin and look for the nucleus. It is obscured by the chlorophyll.

Make a drawing showing all oj the points observed. Look through the stock cultures for other forms of Mastigophora, such as Traclielomonas, Perancina, Pliacus, etc. It is desirable to make drawings of the different forms