Flagellates and swimming colonies
Euglena
Euglena (euglenids)
Green spindle-shaped cells that swim with one flagellum and, when they stop, squirm and change shape.
What to look for
- Elongated green cell with a red eyespot near the front.
- One emergent flagellum at the front (often hard to see without careful focusing).
- Shape change by squirming (metaboly) when not swimming: the cell bulges and contracts like a slug.
Size in the field
Small at 100×: green specks that move. Use 400× for the eyespot.
Where to find it
Puddles, farm ponds and ditches rich in nutrients; can turn water green.
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