Coloured scanning electron micrograph (SEM) of testate amoebas from the soil of the Northern Black Forest, Germany. On top are two small ovoid Assulina sp., at left is a small Trinema with a round, toothed mouth, at far right and left are Nebela militaris and the large amoeba at centre an Euglypha sp. Also seen are pollen grains and bacteria. Testate amoebae are a polyphyletic group of unicellular amoeboid protists. They differ from naked amoebae in the presence of a test, or shell, that partially encloses the cell, with an aperture from which the pseudopodia (false-feet) emerge. The test provides the amoeba with protection from predators and environmental conditions. Magnification: x700 when printed at 15cm wide.