FLAGELLATED PROTOZOA 



57 



color is due to a substance termed chlorophyll which, with the 

 aid of sunlight, is able to manufacture starch which in turn, is 

 built up into proteid matter which serves as food (see Chapter 

 V). Another colored structure is also found in Euglena 

 although it is not so conspicuous as the green chromatophores. 



I 'IG. 25. Gonium pectorale ,a colony of flagellated protozoa consisting of sixteen 

 cells arranged in a flat plate, three on a side and four in the center. Photograph 

 from a preparation. 



This is the red " eye-spot" or stigma which is more sensitive 

 to light than other parts of the protoplasm and is often spoken of 

 as a rudimentary eye-spot. In many cases it is accompanied 

 by a lens-like body which may concentrate light rays on a 

 particular spot and so act as a directive agent; at any rate 



