Hannaea inaequidentata, details of pre-normal vegetative valves, internal view, SEM 131, 132 two apices of Fig. 126 showing two rimoportulae per valve (two arrows) 133 middle part detail of Fig. 127 showing swollen central area and ghost striae 134 detail of Fig. 128 showing the bi-constricted middle part and ghost striae 135, 136 two apices of Fig. 130 showing two rimoportulae per valve. Scale bar: 2 μm (131–136).