^7 



15a Raphe evident on at least one valve 16 



15b Raphe not evident, concealed in a keel or wing 35 



l6a Valves similarly ornamented, raphe on both valves 19 



l6b Valves not similarly ornamented, raphe on one valve, 

 opposing valve with pseudoraphe, or with rudimentary 

 raphe near valve poles 17 



17a Valves elliptical, never linear, sometimes bent along 

 the apical axis - COCCONEIS 



Fig. 62. Cocconeis diminuta , ( 5 ), cells 7-15M long, 5-<?u wide, flat; 

 raphe less valve with 32 delicate striae in 10u; raphe- 

 bearing valve with 13 coarsely punctate striae in lOu. 

 X 1000. 



valve valve 



with raphe without raphe 



Notes 



