26 



Fig. 18. Cyclotella Kutzingiana , (3), cells 10-20u in diameter; 

 center ornamentation highly variable. X 1000. Common 

 in Great Lakes. 



valve views 



Notes : 



Fig. 19. Cyclotella Meneghiniana , (12), cells 10-30u in diameter; 

 heavy marginal costae give impression of scalloped 

 border. X 1000. Widely distributed. 



valve view 



girdle view 



Notes : 



Fig. 20. Cyclotella michiganiana , (ll), cells 5-20u in diameter; 

 valve margin with pronounced rim. X 1000. 



valve views 



Notes : 



