172 ANIMAL BIOLOGY 



it slowly flows about the one-celled plant or animal and finally 

 ingulfs it. The processes of digestion, assimilation, respiration, 

 excretion, and reproduction (Fig. 121) are much the same in amceba 

 as in paramecium. Both these animals belong to a group of animals 

 known as the Protozoa (Greek protos = first or simplest + zoon = 

 animal) . 



FIG. 121. An amoeba dividing. 



127. To show that the higher animals are composed of 

 many cells. Laboratory study. 



Frogs are continually shedding parts of their epidermis, 

 and pieces of this thin membrane are likely to be seen cling- 

 ing to a frog in an aquarium or floating in the water. Secure 

 a piece of this membrane, spread it on a slide, add a drop 

 of water and a cover glass, and examine with the low power 

 of the microscope. 



1. Describe the form and color of each cell. 



2. In each cell notice a body, usually near the center and 



slightly more dense than the rest of the cell. This is 

 the cell nucleus. (If the nucleus does not show 

 clearly, add a drop of iodine to the membrane.) 

 The rest of the cell is the cell body. 

 a. Name, now, two parts of a cell of the frog's epidermis. 



