Plate P1. Illustrations of taxa, sample, and slide number. Scale bar = ~20 µm unless stated otherwise. Scanning electron microscope (SEM) photographs have varying scale bars. 1. Adnatosphaeridium multispinosum (Sample 189-1172D-15R-3, 40-42cm) (1). 2. Aio

Plate P1 (continued). 25-28. Cerodinium sp. A; (25-27) Sample 189-1172D-24R-5, 67-69 cm (2); note elongated endocyst and short antapical horns; (28) Sample 189-1172D-24R-5, 130-133 cm (1); this specimen is somewhat comparable to Cerodinium diebelii, but lacks the longer antapical horns typical for that species. 29. Cerodinium dartmooria (Sample 189-1172D-19R-3, 40-42) cm (1). 30, 31. Cerodinium speciosum; (30) Sample 189-1172D-20R-7, 40-42 cm (1); (31) Sample 189-1172D-21R-3, 40-42 cm (1). 32, 33. Cerodinium striatum (Sample 189-1172D-24R-5, 36-38 cm) (1). 34, 35. Charlesdowniea edwardsii group (Sample 189-1172D-11R-5, 40-42 cm) (1). 36. Cleistosphaeridium diversispinosum (Sample 189-1172D-14R-1, 40-42 cm) (2).