The genus "Difflugia" is the oldest and most diverse of the testate amoebae. Studies surrounding "Difflugia" have been centered around species found mostly in Europe and Africa. She earned her doctorate in 1904 with a dissertation on Difflugia urceolata Carter, a protozoa. Smaller species of "Difflugia" are found to consume bacteria as well as algae and fungi. The genus Difflugia is the oldest and most diverse of the testate amoebae. "Difflugia" are testate amoebae with an agglutinate shell. "Difflugia" are particularly common in marshes and other freshwater habitats.