Plate P26. 1. Thalassiphora delicata Williams and Downie 1966c. 350x. 2. Thalassiphora? spinosa (Clarke and Verdier 1967) Foucher 1975. 350x. 3, 4. Triblastula utinensis O. Wetzel 1933b; (4) left lateral view. Both 350x. 5. Trichodinium castanea Deflandre 1935 ex Clarke and Verdier 1967. 400x. 6. Trigonopyxidia ginella (Cookson and Eisenack 1960a) Downie and Sarjeant 1965. 550x. 7. Trinovantedinium applanatum (Bradford 1977) Bujak and Davies 1983; dorsal view (450x), courtesy of M.R. Bradford. 8. Trinovantedinium glorianum (Head et al. 1989b) de Verteuil and Norris 1992. Ventral view of dorsal surface. Holotype (450x), courtesy of M.J. Head. 9. Trithyrodinium evittii Drugg 1967. 400x. 10, 11. Trithyrodinium suspectum (Manum and Cookson 1964) Davey 1969b; (10) 425x; (11) optical section (500x). 12–14. Unipontidinium aquaeductum (Piasecki 1980) Wrenn 1988; (12) scanning electron micrograph (SEM), dorsal surface (850x); (13) dorsal view of ventral surface (750x); (14) dorsal view of dorsal surface (850x). 15–18. Wetzeliella gochtii Costa and Downie 1976; (15) dorsal view of dorsal surface (300x); (16) same specimen as 15, dorsal view of ventral surface (300x); (17) ventral view of ventral surface (300x); (18) same specimen as 17, ventral view of dorsal surface (300x). 19, 20. Wetzeliella meckelfeldensis Gocht 1969; (19) ventral view of ventral surface (250x); (20) same specimen as 19, ventral view of dorsal surface (250x).