28 



Fig. 2k. Cyclotella striata , (U), 

 cells 10-50u in diameter. 

 Has a circular shadow line 

 passing through the costae. 

 X 1000. In Delaware and 

 Hudson Rivers. 



valve view 



Notes 



Notes on other species of CYCLOTELLA 



6b Valve margin otherwise; central area not sharply distinct 

 from margin; valves with radial rows of punctae or with 

 geometric facets 



7a Punctae in multiseriate rows near valve margin, each row 



gradually or abruptly becoming uniseriate toward the center; 

 marginal spines always present.- STEPHANODISCUS 



Fig. 25. Stephanodiscus astrea (3), cells 

 10-30u in diameter; spines not at 

 end of each row of punctae. Outer 

 punctae in double to quadruple rows, 

 12 punctae in lOu. X 1000. Widely 

 distributed. 



valve view 



Notes 



