These are small fresh
water organisms. Based on molecular data, euglenoids are thought to be closely
related to zooflagellates. They are plantlike in their pigments. One third of
all genera have chloroplasts, the rest do not. Those which lack chloroplasts ingest
or absorb their food. Euglenoids grown in the absence of light lose their
chloroplasts and become heterotrophic. Pyrenoids produce carbohydrates.
Their chloroplasts are
like green algae i.e. surrounded by three rather than two membranes. Euglenoids
have two flagella, one of which is much longer and projects out of the anterior
vase shaped invagination. Near the base of the flagellum is an eyespot. Body is
covered by pellicle composed of protein strips so they can assume different
shapes. As in certain protozoa there is a contractile vacuole. Euglenoids
reproduce by longitudinal cell division and sexual division is not known.
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Euglenoids
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