8^ 



Notes on other species of EPITHEMIA. 



38b Raphe and axial area without a "V "-shaped medial 

 extension 



39 



39-a Raphe canal with pores, valves symmetrical to longitudinal 

 axis - DENTICULA 



Fig. 133. Denticula elegans , (5), cells 15-40u long, 5-7U wide; 

 3-5 transverse ribs in lOu; 15-17 striae in lOu. 



valve view 



girdle view 



Notes : 



39b Raphe canal without pores, valves asymmetrical to the 

 longitudinal axis - RHOPALODIA 



