Family Centropyxidae Jung, 1942
Diagnosis: Lobose testate amoebae with shell of granular organic material, dorsally with more or less mineral particles or diatoms, ventrally smooth or with much smaller grains; dorsal surface rounded, ventral side flat to concave, with a ventral aperture, which may be circular to uneven, but displaced towards one end; shell may be flattened at the apertural end; at the posterior end or all around the periphery some spines may be present.
Type genus: Centropyxis.

Test of Centropyxis discoides, see detail below

The test consists of an organic layer of granular structure with embedded xenosomes, here several kind of diatoms, some with remnants of the chloroplast still present.