80 



35a Keel elevated into a lateral "wing" or flattened on the 



valve surface 37 



35b Keel elevated into an axial "wing" extending along the 



central axis of the valve 36 



36a Keel sigmoid, usually seen in girdle view (hour-glass-shaped), 

 frustule twisted along the longitudinal axis; girdle broad with 

 many longitudinal folds - AMPHIPRORA 



Fig. 127. Amphiprora alata, (5), cells *»-0-l60u long, 20-60u wide; 

 striae fine,punctae discernable. X 1000. Abundant in 

 the southwest. 



girdle view 



Notes : 



Fig. 128. 



Amphiprora paludosa , (5), cells 30-130u long, 15-50n wide; 

 striae fine, punctae not discernable. X 1000. Abundant 

 in the southwest. 



i - .-^^cffiffltoa* 6 



girdle view 



Notes : 



