AMCEBA 55 



pseudopodia? Is the boundary between the two parts a 

 sharp one? Which layer is the more fluid? Is there a 

 definite membrane about the animal ? 



Within the entoplasm may be seen food vacuoles which 

 are usually rather small and spherical, though they may be 

 quite large and of irregular shape, depending upon the kind 

 of food which has been eaten. Do you find what might be 

 considered as lifeless material such as crystals, oil drops, and 

 the like? In the entoplasm may also be found the contractile 

 vacuole, a transparent, spherical body which disappears and 

 reappears at intervals. Its function appears to be excretory. 



Sometimes the nucleus can be seen. This is a circular or 

 oval, denser body, usually granular in appearance. Does 

 it occupy a definite and constant position in the amoeba? 

 If it cannot be seen in the living animal examine one of the 

 stained and mounted specimens. 



Make a drawing about two inches in diameter, fill in, and 

 label all the details mentioned above. 



II. Physiology. 



1. Movements. Is motion continuous? Regular? How 

 is it produced? Is there any definiteness of direction? 

 Watch the formation of a pseudopodium and describe what 

 part the ectoplasm and entoplasm play in the process. Are 

 the currents in the entoplasm at all constant? Where are 

 they the swiftest, where slowest? Trace on paper the path 

 that an amoeba has taken in the time under observation. 



2. Nutrition. If opportunity oft'ers determine how an 

 amoeba eats, and how it gets rid of waste matter. From 

 an examination of the food vacuoles determine, if possible, 

 what the animal eats. Look especially for diatoms and 

 desmids and for small protozoa. Is there a definite course 



