English: Ciliata: 1, 2, Heterotrichaceae; 3-7, 23-24, Oligotrichaceae; 8-22, 25, 26, Peritrichaceae.

1, Spirostomum ambiguum, Ehr.; on its left side oral groove and wreath of membranellae; a, moniliform meganucleus; b, position of contractile vacuole.

2, Group of Stentor polymorphus, O. F. Müller; the twisted end of the peristome indicating the position of the mouth.

3, Tintinnus lagenula, Cl. and L., in free shell.

4, Strombidium claparedii, S. Kent.

5, Shell of Codonella campanella, Haeck.

6, 7, Torquatella typica, Lank. ( = Strombidium according to Bütschli); p, oral tube seen through peristomial wreath of apparently coalescent membranellae.

8. Basal, and 9, side (inverted) views of Trichodina pediculus, Ehr.; a, meganucleus; c, basal collar and ring of hooks; d, mouth; contractile vacuole and oral tube seen by transparency in 8.

10, Spirochona gammipara, Stein; a, meganucleus; g, bud.

11, 12, Vorticella microstoma, Ehr.; d, formation of a brood of 8 microgametes c by multiple fission; b, contr. vacuole.

13, Same sp. in binary fission; a, meganucleus.

14, V. nebulifera, Ehr.; bud swimming away by posterior wreath, peristome contracted; e, peristomial disk; f, oral tube.

15, V. microstoma; b, contr. vacuole; c, d, two microgametes seeking to conjugate.

16, V. nebulifera, contracted, with body encysted.

17, Same sp. enlarged; c, myonemes converging posteriorly to muscle of stalk; d, micronucleus.

18, Carchesium spectabile, Ehr.; (×50).

19, Nematocysts of Epistylis flavicans. Ehr. (after Greeff).

20, Opercularia stenostoma, St.; (×200); a small colony showing upstanding (“opercular”) peristomial disk, protruded oral undulating membranejand cilia in oral tube.

21, 22, Pyxicola affinis, S.K., with stalk and theca; x, chitinous disk, or true “operculum” closing theca in retracted state.

23, 24, Caenomorpha medusula, Perty, (×250), with spiral peristomial wreath.

25, 26, Thuricola valvata, Str. Wright, in sessile theca, with internal valve (v) to close tube, as in gastropod Clausilia; owing to recent fission two animals occupy one tube.