A euryhaline and polymorphic new diatom,Proteucylindrus taiwanensisgen. et sp. nov.

Abstract
A detailed description of the polymorphism and the fine structure of the frustule of a new diatom, Proteucylindrus taiwanensis gen. et sp. nov., is presented. The valve has 2–4 ocelli and 0–9 labiate processes and the areolae are simple pores. The ocelli do not protrude in the freshwater media but do so distinctly in seawater media with salinities above 5‰. The girdle is composed of several segmented bands. Each band has three segments. The sexual reproduction is by oogamy.