FIGURES 13–18. SEM. Cyclotella utahensis. Internal views. Fig. 13 in New and Interesting Diatoms (Bacillariophyta) from Blue Lake Warm Springs, Tooele County, Utah

FIGURES 13–18. SEM. Cyclotella utahensis. Internal views. Fig. 13, Full valve showing relative positions of the central fultoportula and the rimoportula (black arrow). Fig. 14, Full valve of a small specimen lacking obviously recessed ribs. Fig. 15, A large specimen with two central fultoportulae and two recessed ribs between some primary ribs. Fig. 16, Areolae with cribra visible between ribs. Fig. 17, View of the sessile rimoportula and two recessed ribs between a pair of primary ribs. Fig. 18, Marginal fultoportulae with three satellite pores. Scale bars: Figs 13–15: 1 µm; Fig. 16: 0.1 µm; Figs. 17–18: 0.5 µm.