FIGURES 83–94. Chaetoceros contortus. Figs 83–84, 88–92: culture material, strain PMFCO2. Fig. 93: strain PMFCO1. Figs 85–87: field material. Figs 83–86: LM. Figs 87–90, 92–94: TEM. Fig 91: SEM. 83) Complete chain showing orientation of the setae. 84) Middle part of a chain showing several small chloroplasts and typical hexagonal aperture. 85) Part of the chain with specialized intercalary setae. 86) Middle part of the chain with resting spores. 87) Valve face and mantle showing the reticulate area within the central annulus and small dots on the end of some costae (arrow). Note the hyaline rim with a rectangular projection (arrowhead). 88) Valve face with network of costae. 89) Sibling valves in valve view showing the hyaline rim on the marginal ridge. 90) Terminal valve with a club-like shaped external process of the rimoportula and rectangular siliceous projections (arrow). 91) Detail of the terminal valve with hole of the terminal process from the internal view. 92) Detail of a terminal valve with club-shaped rimoportula. 93) Detail of a girdle band. 94) Detail of a seta. Scale bars: 83=50 μm; 84–86=10 μm; 87, 89=2 μm; 88, 90–92, 94=1 μm; 93= 0.5 μm.