2 Laboratory Guide in Zoology- 



case the Amoeba is moving in a definite direction, 

 notice whether the progress is being made by means 

 of a single broad pseudopod or by more than one. 

 Determine whether a change in the direction of move- 

 ment is made by pushing any part of the surface of 

 the protoplasm outward. Is it true that the body of 

 the animal is thus temporarily differentiated into an- 

 terior and posterior parts ? 



III. — Watch the Amoeba as it approaches some small, 

 one-celled plant. Wait patiently to see, if possible, the 

 plant-cell taken into the body of the Amoeba. How is 

 this accomplished ? Is any water taken into the body 

 with the plant-cell ? 



IV. — Focus carefully upon a round, nearly transparent 

 spot generally to be seen in the ectosarc : this is the 

 contractile vacuole. Watch this spot patiently to see 

 whether it ever disappears. If it does thus disappear, 

 watch for its reappearance. 



V. — In the largest specimens look for the roundish 



nucleus, more granular than the endosarc surrounding 

 it. If it is not visible in the living Amoeba, stain the 

 specimen with iodine or carmine to bring it out. 



VI. — One is rarely fortunate enough to see the process 

 of fission in the Amoeba, but sometimes this happens. 

 If a large Amoeba is seen partially divided near the 

 middle, watch it closely to see if division is taking 

 place; if so, continue watching until the process is 

 completed. 



VII. — Draw an Amoeba, making the sketch at least an 

 inch in diameter: show its form, the distinction between 

 the ectosarc and endosarc, the contractile vacuole, and 

 the nucleus. 



