ALGLE 



113 



often more abundant, a single branch from the main body 

 bears several lateral oogonia and a terminal coiled anther- 

 idium (Fig. 102, B). 



The two important facts illustrated by Vaucheria are 

 the coenocytic body and the development of special cells to 

 act as sex organs. 



FIG. 103. Spirogyra: one complete cell, showing the spiral, band-like chloroplasts, 

 with embedded pyrenoids, and a nucleus (near the center) swung by radiating 

 strands of cytoplasm. 



* 69. Spirogyra. 

 This is one of the most 

 common of the pond 

 scums, occurring in 

 slippery and often 

 frothy masses of deli- 

 cate filaments floating 

 in still water or about 

 springs. The filaments 

 are simple, and are not 

 anchored by a special 

 basal cell. 



The cells contain re- 

 markable chloroplasts, 

 which are bands pass- 

 ing spirally about with- 

 in the cell-wall (Figs. 

 103 and 104). These 

 bands may be solitary 



Or Several in a Cell, and FlG - 104. Sptnw/ra: A-C, various stages in the 



development of sexual tubes; D, a completed 



form very striking and 



