Large species (12.0-15.0µm) of Sullivanica has a symmetrical diagonal cross.
Sullivan, F. R., 1964. Lower Tertiary nannoplankton from the California Coast Ranges. I. Paleocene. University of California Publications in Geological Sciences 44, 163-227.
Varol, O., 1992a. Sullivania a new genus of Palaeogene coccoliths. Journal of Micropalaeontology 11, 141-150.