A redescription of morphologically similar species from the genus Euglena:E. laciniata, E. sanguinea, E. sociabilis, and E. splendens¹

E uglena sanguinea (Ehrenberg 1831) was one of the first green euglenoid species described in the literature. At first, the species aroused the interest of researchers mainly due to the blood‐red color of its cells, which, as it later turned out, is not a constant feature. Complicated chloroplast morphology, labeled by Pringsheim as the “peculiar chromatophore system”, made the correct identification of the species difficult, which is the reason...