Figs 17–28.

Leptopharynx costatus gonohymen from life (17–19) and after protargol impregnation (20–28). 17. Right side view of a representative specimen of the large morph, length 55 μm. Note the deep furrows right of kineties 2–4 and the narrow oral basket. Arrows mark notches formed by the furrows of the right side. 18, 19. A resting (5–6 μm) and an exploded extrusome. 20–22. Ventral view of a paratype specimen of the large morph. Note the right-angled M2 and M3 (small arrows and (21, 22)) and the broadly elliptical oral basket opening. 23–26. Right and left side view (24, 26) and adoral membranelles (23, 25) of the hapantotype specimen for the large morph, length 53 μm. Arrows mark notches formed by the right side furrows. Arrowhead denotes a line produced by the nasse kinetosomes. Note the narrow oral basket and the right-angled M2 and M3, forming a triangular space in between. Compared to the ventral view (20, 21), the lateral view shows M2 from the narrow side and M3 from the wide side. 27, 28. When dividing, both morphs show three adoral membranelles in proter and opisthe. A, group A basal bodies; C, group C basal bodies; K1–9, somatic kineties; M(1–3), adoral membranelles; MA, macronucleus; MI, micronucleus; NK, nasse kinetosomes; OB, oral basket; OP, oral primordium; PC, postoral complex; PO1–4, preoral kineties. Scale bars 20 μm (17, 24, 26), 15 μm (20, 27), and 10 μm (28).