THE PEOTOZOA 



or a scrap of thin paper or a bit of wax by the edge of 

 the drop, then, carefully place the cover- glass on the 

 drop, resting one edge upon the hair or paper so that 

 the cover may not crush the specimens by its weight. 

 Care must be taken to keep the specimens supplied with 

 water. This can be done by placing a drop at the edge 

 of the cover-glass from time to time. Capillary attrac- 

 tion will draw the drop between the slide and the cover. 

 Examine the preparation first with a low, then with a 

 high power. Be careful not to mistake for Protozoa 

 various microscopic worms and crustaceans, usually dis- 

 tinguishable by their appendages. 



General Questions. — How many different shapes can 

 you distinguish? What variations in size? In color? 

 Is the body always symmetrical ? What determines the 

 shape of the body ? Is there any distinction between 

 head and iody'i What various motions have these ani- 

 mals? By means of what organs are the movements 

 produced ? Do all of the Protozoa which you find pos- 

 sess the same kind of motor organ? In what manner 

 are the motor organs connected to the body ? Does the 

 body contain hlood'i Can you find any organ corre- 

 sponding to a heart ? Stomach ? Lung or gills ? Brain ? 

 How do these animals eat ? Digest their food ? Breathe ? 

 Are eyes present? How do the animals find their way 

 about ? Do they fed ? Are nerves visible ? How do 

 the Protozoa know what to eat ? Is their soft body, 

 consisting mainly of protoplasm, protected in any way ? 

 What means of offence or of defence have these ani- 

 mals ? Means of distribution ? How do you account 

 for their very wide distribution ? For the possibility of 

 raising them artificially in the ways described above ? 



Make sketches of six of the different forms which you 

 find. 



