52 

 Rotes on other species of ACHNANTHES. 



l8b Valves asymmetrical about the transapical plane, one valve vith 

 completely developed raphe, opposing valve with rudimentary 

 raphe near valve poles - RBOICOSPHENIA 



Fig. 71. Rhoicosphenia curvata , ( 5 ), cells 12-75u long, k-8\i wide," 

 curved and wedge-shaped in girdle view; 12-15 striae in 

 lOp . X 1000. Widely distributed. 



■^ttBrnnrnrnn milium 



f-piw irrmn 



"* 'TWHIIIIIMII 



JiiilHIIIIIIIIU 



valve views girdle view 



Notes: 



