Euglena in the context of Euglena viridis

Paramylon is a carbohydrate similar to starch. The chloroplasts found in Euglena contain chlorophyll which aids in the synthesis of carbohydrates to be stored as starch granules and paramylon.

Infusoria is a word used to describe various freshwater microorganisms, including ciliates, copepods, euglenoids, planktonic crustaceans, protozoa, unicellular algae and small invertebrates. Some authors (e.g., Bütschli) have used the term as a synonym for Ciliophora. In modern, formal classifications, the term is considered obsolete; the microorganisms previously and colloquially referred to as Infusoria are mostly assigned to the clades Diaphoretickes (e.g. ciliates, most algae), Amorphea (e.g. crustaceans and other small animals) and Discoba (euglenids).

In other contexts, the term is used to define various aquatic microorganisms found in decomposing matter.

The periplast is one of three types of cell-covering of three classes of algae. The cryptomonads have the periplast covering. The Dinophyceae have a type called the amphiesma, and the Euglena covering is the pellicle.