72 



THE EUGLENA 



or better, observe the changes in shape of a single individual, 

 changes are termed euglenoid movements. 



These 



Exercise 2. — General Structure. 



(c) Can you distinguish anterior and posterior ends? A slight 

 notch in the profile of one end marks the opening of the gullet within 

 which is the attached end of the flagellum, a long threadlike process 

 difficult to see when in motion. Understand from textbook or lectures 

 how this is used in locomotion. Make a clay model or a figure to 

 show these external features, 



(d) Begin a figure 10 cm. long, showing the outlines of an ex- 

 panded euglena. Also make an outline of a contracted euglena on the 



Phacus 



Peranema 



Sphaerella 



Cercomonas 



Monoslga 



Fig, 36. — Representative Sarcodina (upper row) and Mastigophora (lower 

 row). Maatujamccba, which has a flagellum and pseudopodia, is classilied 



as a mastigophoran, 



(Drawn by C. E. WUson.) 



same scale. As you proceed, add details to the first drawing, labeling 

 fully. The chlorophyl, or green coloring matter, is contained in bodies 

 known as chloroplasts. Some of the larger species of euglena usually 

 contain ringlike masses of paramylum, one of the starches. What can 

 you infer, from the presence of chlorophyl, concerning the nutrition 

 carried on by the euglena? Do you find a nucleus? What other 

 structures can you find inside the cell or on its outer surface? There 

 is a spot of red pigment, the so-called eye-spot, near the anterior end. 

 The lighter spot near the anterior end of the cell is a group of vacuoles 



