Polysegmentina Cushman 1946

Test discoidal, circular to ovate in outline, laterally compressed, early chambers in sigmoiline arrangement and with more than three chambers per whorl, later planispiral and partially involute, chambers increasing rapidly in breadth and height, and in number up to five to seven per whorl, occasional specimens may tend to uncoil in the final stage, proximal interior of chambers with tiny narrow longitudinal ridges just distal to the sutures, adjacent ridges may coalesce inward to form complete tubes, the interridge areas opening to the exterior as numerous narrow tunnels where the tubular structures merge into longitudinal external ridges that partly cross the chamber; wall calcareous, imperforate, porcelaneous, thick; aperture in the early stage with a tooth that in later chambers rapidly becomes more complex and finally has numerous openings in a narrow and elongate convex trematophore plate. Holocene; Pacific. (Loeblich & Tappan, 1987, Foraminiferal Genera and Their Classification)