Some euglenoids have pellicles with few, longitudinally arranged pellicle strips. These organisms are usually rigid and do not exhibit metaboly. Other euglenoids have many helically arranged strips. These organisms often exhibit a wriggling motion known as metaboly. Longitudinal vs. Helical Pellicle To see metaboly in action, view the Quicktime movie.
Euglenoids have an extensive endomembrane system.
The ER also serves as the major source of membrane for the Golgi apparatus. Euglenoids have some of the largest dictyosomes found among eukaryotes, with large numbers of individual cisternae making up each Golgi stack. Each mitochondrion is surrounded by two membranes. The inner membrane folds into the matrix and forms the cristae. In euglenoids, the cristae arepaddle-shaped.