4 S. O. MAST 



2. STRUCTURE OF GONIUM 



Gonium is a thin flat rectangular structure somewhat over 0.1 

 mm. wide. It consists of 16 cells or zooids loosely united with 

 protoplasmic strands which penetrate a gelatinous substance 

 found in the intercellular spaces (fig. 1). Each zooid contains 

 among other things, a relatively large chloroplast, a prominent 



o.o3 ni.m- 



Fig. 1 Camera lucida drawing of Gonium as seen from the posterior surface. 

 Each colony contains 16 zooids, all situated in the same plane, z, zooids; e. eye- 

 spot; p, pyrinoid; s, strands connecting the zooids; /, flagella; mm, projected 

 scale. The arrow indicates the usual direction of rotation. The eye-spots are 

 located at the outer surface near the anterior end of the zooids. Note that they 

 are a little to one side of the middle of this surface. 



