Figure 3 in The search finds an end: the morphologically chimeric hysterocinetids belong to the subclass Hymenostomatia (Ciliophora: Oligohymenophorea)

Figure 3. Hysterocineta bellerophon in vivo (A) and asser protargol impregnation (B–L). A, less-side view of a representative specimen. B, oral ciliary paưern. Membranelle M1 is made up of two rows of basal bodies and runs only on the peristome. Membranelle M2 is cut in two segments: (i) the distal segment M2 is built from two rows of basal bodies and runs beside M1, (ii) the proximal segment M2' is composed of three rows of basal bodies and extends beside M3. Membranelle M3 consists of two rows of basal bodies and starts at the infundibular entrance. C–F, I–L, less-side overviews, showing the variability of body shape and size as well as of the nuclear apparatus (shaded grey) and sucker (shaded yellow). Dashed circles represent contractile vacuole. G, H, the ciliary paưern of the less (G) and the right (H) side. Arrows mark a posterior secant system each on the ventral and the dorsal margin of the right body side. Abbreviations: CV, contractile vacuole; IF, infundibulum; M1–3, membranelles 1–3; MA, macronucleus; PM, paroral membrane; S, sucker; SK, somatic kineties. Scale bars = 50 µm (A, G, H), 100 µm (C, D, E, F, I, J, K, L).