Haeckel
Cephalis very small, ovate, hyaline. Thorax large, conical, with ca. 10 well defined longitudinal rows of subquadrate pores rapidly increasing in size toward the base. Pores are usually not aligned transversely. The form described as Plectopyramis dodecomma Haeckel differs from Plectopyramis circumtexta in that pores are aligned transversely as well as longitudally. Bathropyramis woodringi is also similar to the above, but has thicker longitudinal bars and aligned horizontal (transverse) bars. Shell height: 100-300 µm.
Ref.: Riedel (1958), Nigrini and Moore (1979).