Amphistegina quoyi; Print; Amphistegina is a genus of foraminiferal protists included in the Rotaliida with a stritigraphic range extending from the Eocene to recent and a cosmopolitan distribution. The test is an asymmetrically biconvex trochospiral that may be bi-involute or partially evolute on the spiral side. Chambers are numerous; broad. and low; strongly curved back at the periphery to form chamber prolongations. The umbilical side is stellate; like that of Asterigerina; and has a distinct umbilical plug. The wall is calcareous; optically radial; the surfacce finely perforate and smooth overall. The periphery angular to carinate (keeled); the aperture an interiomarginal slit on the umbilical side; bordered by a lip.