FIGURES 173–182. Chaetoceros tortissimus. Figs 174–175, 178 in The planktonic diatom genus Chaetoceros Ehrenberg (Bacillariophyta) from the Adriatic Sea

FIGURES 173–182. Chaetoceros tortissimus. Figs 174–175, 178: field material. Figs 173, 176–177, 179–182: culture material, strain PMFT1. Figs 173–176: LM. Figs 177–178, 181–182: TEM. Figs: 179–180: SEM. 173) Complete chain with a slight torsion showing orientation of the setae. 174) Complete chain composed of cells with short pervalvar size strongly twisted around the chain axis. 175) Middle part of a chain showing hexagonal apertures. 176) Intercalary cells with one parietal plate-like chloroplast positioned around the girdle. 177) Detail of the valve face with network of costae some ending in round spots (arrow). 178) Two overlapping sibling valves showing the valve ornamentation and the elongated pores near the bases of the setae (arrows). 179) Sibling valves with the elongated pores (arrows). 180) Detail of the proximal part of the seta with the large elongated pore. 181) Detail of the girdle band. 182) Detail of a seta. Scale bars: 173–175=20 μm; 176=10 μm; 178, 179=5 μm; 177=2 μm; 180–182=0.5 μm.