Multicellular algae, cylindrical spiral filaments, solitary or clustered, filaments 5-10 micron in diameter, apex obtuse, helix 2-7. The algae can vibrate and rotate, often rotating rapidly like a vertical axis and crawling forward. The cell contains a homogeneous substance without a real nucleus. The algae body is an unbranched filament composed of a single row of cells. The glial sheath has no or only a very thin sheath and has a regular spiral shape to form the reproductive segment of the algae. The conidia and the spore of the posterior wall. Because the amount of phycoerythrin and phycocyanin in the body is different, they present different body colors, such as blue-green, yellow-green or purple-red. And there is a thin diaphragm wall. It is a simple reproduction way of prokaryotes and can be directly split.