A, B Two specimens of Litonotus lamella, arrowheads mark the firm pellicle lines in A and the macronucleus in B. C Coleps hirtus D, E Gonostomum affine cells, arrowheads show the curved adoral zone of membranelles typical of the genus F Vorticella picta G, H live and protargol stained cells of Tetrahymena pyriformis, showing the oral apparatus with three adoral membranelles and paroral membrane (double arrowhead) and two of the ciliary rows (arrowheads) I, J representative specimens of Climacostomum virens, arrowhead in J marks the stained macronucleus. MA = macronuclear nodule. Scale bars: 25µm.