Plate P4. Magnification for light micrography is 2200x; magnification for scanning electron micrography (SEM) specimens is indicated. Light micrography: PH = phase-contrast light, PL = plain transmitted light, XP = cross-polarized light. 11, 12. Cribrospaerella ehrenbergii, Sample 173-1069A-12R-3, 27-29 cm, PH (11) and XP (12).