WunderkanoneExploring the Microscopic World

Arcella

Arcella vulgaris

Arcella gibbosa

Arcella (Ehrenberg, 1832) is a genus of ususally round testate (shelled) amoebas. The test (shell) is composed of organic material and has a central hole at the underside (aperture).

Young Arcella tests are nearly transparent and become darker and brown over time due to the inclusion of iron and manganese. Most Arcella are binucleate. There are over 50 species with different forms of the test.