SEM Photograph: (Borne and Cronin, ms, pl. 4, fig. 2) Scale is 0.08 mm. (Locality CJ89-20-01: Río Banano, Limón Province, Costa Rica; Río Banano Formation). Left valve, female.
Morphologic Description: Straight and simple marginal pore canals.
Holotype: USNM 35422 [reported broken (Bold, 1963a) and lost (Forester, 1980)] (Holotype locality: Yorktown Formation of Virgina. Pliocene). Reference material: HVH No. 1073 (K.E. Young 34, near Ward, Florida, Choctawhatchee State, Late Miocene).