Cells are colorless spirilla, pointed at the ends and containing sulfur globules. Polar flagella, in some cases united in a tuft, are visible in the light microscope. Thiospira winogradskyi is 2-2.5 µm wide and up to 50 um long. “Thiospira lipunctata” is 1.7-2.4 X 6.6-14 µm.