4 Laboratory Guide in Zoology 



III. — Notice the green color of the Euglena due to chlo- 

 rophyl — the green coloring-matter of plants. By 

 means of this the creature is able to build up its sub- 

 stance as plants do. Add a little alcohol, and notice 

 what effect it has upon the color of the Euglena. 



IV. — After the alcohol has thus been added, notice the 

 oblong bodies near the middle of the Euglena : these 

 are paramylum grains. 



V. — In a freshly mounted specimen study the proto- 



plasm at each end of the body. How does its color 

 differ from that of the central part of the body.'' Near 

 the front end see a distinct red spot, often called the 

 eye-spot. Near this eye-spot distinguish the large clear 

 reservoir with the vacuole beside it. The distinction 

 between these may be plainly seen only in the largest 

 and best specimens. 



VI. — Stain the specimens with iodine or carmine; then 

 look for the nucleus, a round spot near the middle of the 

 body. If it does not show clearly, take a fresh slide, 

 treat with alcohol to dissolve out the chlorophyll, and 

 then stain. 



VII. — Make a drawing at least an inch long, showing an 

 outline of a free-swimming Euglena and all the struc- 

 tural details you have seen. 



VIII. — Study as many stages of the round Euglenas under- 

 going fission as you can find. Make sketches of two or 

 three specimens showing different phases of the process. 



