Difflugia are a type of testate amoebae characterized by their agglutinate shells, which are composed of various mineral particles known as xenosomes, acquired from their environment. Different species of Difflugia have distinct tests, varying in shape and size. While most species have a single nucleus, some are multinucleated, with larger species often possessing vesicular nuclei instead of the typical oval shape. All Difflugia species feature an epipodium, a terminal aperture in their structure. Their size ranges from 15μm to 500μm. During cell division, the particles used to construct the test are passed on directly to the daughter cell. The strength of the test varies among species, categorized as robust, intermediate, or fragile, with robust tests often resulting in irregularly shaped shells, while fragile tests are typically made from diatom crystals.