Uncinataria, [203]
Under arm-plate of Ophiuroidea, [491]
Under basal-plate of Crinoidea—see Infra-basal plate
Undulating membrane, of Flagellata, [111], [115], [123];
of Trypanosoma, [121];
of Dinenympha, [123];
of Stylonychia mytilus, [139] f.;
of Ciliata Trichostomata, [137] f., [145];
of Glaucoma, [153];