Pellicle organisation in Gregarina steini gamonts as revealed by the freeze-etching. A–C. Fractured epicytic folds; cytoplasm of epicytic folds (*), deutomerite cytoplasm (c), ducts (encircled), EF face of the external cytomembrane (Ee), EF face of the internal cytomembrane (Ei), EF face of the plasma membrane (Ep), groove (g), mucus (x), PF face of the external cytomembrane (Pe), PF face of the internal cytomembrane (Pi), PF face of the plasma membrane (Pp), pores (white arrows). D. General view of the epicytic folds showing the grooves (g) with mucus drops (x); cytoplasm of epicytic folds (*), deutomerite cytoplasm (c). E. The cytoplasmic face of the grooves between epicytic folds with micropores and numerous pores (some of them shown by white arrows); cytoplasm of epicytic folds (*), EF face of the internal cytomembrane (Ei), PF face of the external cytomembrane (Pe). The inset shows the detailed view of micropore and four pores of different sizes. F. Fractured epicytic folds showing their IMP alignments (arrowheads) located on the PF of the internal cytomembrane (Pi) and on the EF face of the external cytomembrane (Ee); cytoplasm of epicytic folds (*), EF face of internal cytomembrane (Ei), grooves (g), PF face of external cytomembrane (Pe), pores (white arrows). The inset shows EF of the plasma membrane (Ep) with mucus drops (x). The arrowhead in the circle shows the direction of shadowing.