2 BRANCH PROTOZOA 



tinct line between the clear outer homogeneous layer, or ecto- 

 plasm, and the inner granular substance, the endoplasm. Within 

 the endoplasm is the nucleus, a small, round, denser mass. 



Sometimes the contractile vacuole, a clear sphere of liquid and 

 gas, appears, increases in size, then contracts, and disappears, 

 and a new one is formed. This is supposed to aid in respiration 



m 



5*.'A^ 



Fig. 1. — Amoeba polypodia in six successive stages of division. The dark 

 white-edged spot in the interior is the nucleus. (Schulze.) 



and in carrying off the waste products formed by oxidation, 

 such as carbon dioxid. 



Motion and Locomotion. — Under the microscope the amoeba 

 may be identified by its movements. The body surface will be 

 seen to protrude or rather flow out at one or several points, 

 forming irregular lobes, called false feet, or pseudopodia, which 



