Plate 1. Alexandrium acatenella. Figs. 1-2. LM: ventral view of empty thecae. Cell small to medium, longer than wide, angular to round. Conical epitheca with shoulders; larger than hypotheca. Figs. 3-4. Line drawings. Fig. 3. Ventral view: 1' plate bears ventral pore (vp). Hypotheca with two antapical spines (arrows). Fig. 4. Po comes in direct contact with 1' plate. APC: comma-shaped foramen (arrow).
