Morphology of the arctic, planktonic Navicula pelagica (Bacillariophyceae), with special reference to the setae

The arctic, marine, planktonic diatom Navicula pelagica Cleve (Bacillariophyceae) forms colonies slightly similar to those of Chaetoceros. The structures resembling setae are dislocated bands of the epithecae, attached by their ligula area to the central mucilage pad that keeps the cells together in colonies.