72 



Fig. 109. Navicula bacillum, (5), cells 20-80u long, 10-20u wide; 



central area rounded not quadrangular; middle striae, 12-1^ 

 in lOu, 18-20 striae in lOu near the poles; do not 

 mistake for N. pupula. X 1000. 



valve view 



Notes ; 



Fig. 110. Navicula canalis , (2), cells 10-27u long, 3-5H wide; 

 16-18 striae in lOu. X 1000. 



valve view 



Notes : 



Fig. 111. Navicula conf ervacea , (k), cells 10-28u long, 5~8u wide; 



18-22 striae in lOu; may be found in chains like Fragilaria ; 

 raphe can be seen in girdle view. X 1000. 



valve views 



girdle view 



Notes : 



