22 PROTOPLASM AND THE CELL 



exhibits movement. It can protrude on one side an 

 extension of its body and enlarge that so that all the 

 protoplasm flows into it, retracting the opposite side 

 meanwhile. By so doing, it has changed its position. 

 This type of movement is known as amoeboid viovement^ 

 and is probably common to nearly all protoplasm. 



The one-celled green plant Chlaviydomonas (Fig. 3) 

 exhibits a somewhat higher degree of organization, 

 in that it has a wall surrounding it which prevents 



Fio. 3. — Chlamydomonas, a one-celled plant, r?, nucleus with its 

 chromatin network, nuclear sap, and nucleolus, n'; chr, the green 

 chromatophore of solider protoplasm conUiininj? the green coloring 

 matter, chlorophyll; cyt, cytoplasm; p\j, the pyrcnoid or starch- 

 forming organ of the chromatophore; «, starch grains; c, eye-spot, 

 a solider mass of protoplasm containing a reddish brown pigment, 

 suppasedly an organ sensitive to light; c.r., contractile vacuoles; 

 c.jr., cell wall; c, flagella, hairlikc projections of the cytoplasm by 

 means of which the plant propels itself through the water. 



the organism from changing its shape as a whole. 

 And it has also at one end two projecting, oar-like 

 processes which can be moved rapidly, thereby pro- 

 ducing movement of the entire cell. It has also a 

 green color. This green color will be found to be 



