24 Periodicity in Active Numbers of Soil Flagellates 



SUMMARY. 



1. There is a daily fluctuation in the number of trophic forms of 

 the three species of flagellates Oicomonas sp. (Martin), Cercomonas 

 longicauda and Bodo sp., in the soil of arable fields. 



2. The numbers of bacteria and trophic amoebae in the soil are 

 correlated, varying inversely over a period of 14 days. 



3. Temperature and rainfall appear to have no influence on the 

 numbers of active protozoa in the soil. 



(3 



(4 



(5 

 (6 



(7 



(8 



(9 

 (10 

 (11 



(12 



(13 



REFERENCES. 



Boeck, W. C. (1919). Studies on Giardia microti. Univ. Calif. Publ. xix, p. 86. 

 Bohn, G. (1904). Periodicite vitale des animaux soumis aux oscillations du 



niveau des hautes mers. Comp. Rend, des Seances de Vacad. Sciences, T. 



139, p. 646. 

 Calkins, G. N. (1904). Studies on the life history of Protozoa. Journ. Exp. 



Zool. i, p. 423. 

 Crump, L. M. (1920). Numbers of Protozoa in certain Rothamsted Soils. 



Journ. Agric. Sci. x, p. 182. 

 Cutler, D. W. (1919). Observations on Soil Protozoa. Ibid, ix, p. 430. 



(1920). A method for estimating the number of Active Protozoa in the 



Soil. Ibid, x, p. 133. 



Goodey, T. (1916). Further Observations on Protozoa in Relation to Soil 



Bacteria. Proc. Roy. Soc. B. lxxxix, p. 297. 

 Greciory, L. H. (1909). Observations on the life history of Tillina magna. 



Journ. Exp. Zool. vr, p. 383. 

 Keeble, F. (1910). Plant Animals. 



McClendon (1917). Physical Chemistry of Vital Phenomena, p. 155. 

 Woodcock, H. M. (1916). Observations on Coprozoic Flagellates. Phil. Trans. 



Roy. Soc. B. ccvii, p. 375. 

 Woodruff, L. L. and Baitsell, G. A. (1905). Rhythms in the reproductive 



activity of Infusoria. Journ. Exp. Zool. xi, p. 339. 



(1917). The influence of general environmental conditions on the perio- 

 dicity of endomixis in Paramoecium aurelia. Biol. Bull, xxxiii, p. 437. 



