Volvox and Associated Algae from Kimberley. 515 



ground or in natural depressions, are very characteristic of large areas 

 in Africa. If the rains are good they may fill up yearly or several 

 times each year ; on the other hand they may remain dry for several 

 years in succession. When they do fill, their duration is often very 

 brief, often only a week or two, yet in that time an extraordinarily 

 rich algal flora often develops. Obviously such pools would often 

 form most favourable subjects for intensive observation. The Kim- 

 berley pool is apparently of comparatively recent origin, and it seems 

 probable that far richer results could be obtained by a systematic 

 study of some of the many small temporary pools which form in 

 natural hollows in high veld regions one wet season after another, 

 and have probably done so from time immemorial. 



The present account is as far as is known the first attempt as yet 

 made to describe the seasonal changes in a part at least of the flora of 

 such a transitory pool, and since it is compiled from a series of observa- 

 tions and collections made with one object only, namely the study of 

 the behaviour of the single genus Volvox, it will be obvious that its value 

 as a general seasonal history of the pool is small. It may, however, 

 serve to illustrate the interest and value of a detailed study of the algal 

 vegetation of individual pools of this kind, and it seems time that such 

 seasonal studies should be initiated to supplement our growing 

 knowledge of the systematic side of freshwater algology in South 

 Africa, and to correlate it with the occurrence of the various con- 

 stituents of the rich and varied algal flora of this country under 

 varying local and seasonal conditions. 



RONDEBOSCH, CAPE PROVINCE, 



July 1932. 



BIBLIOGRAPHY, 



Most of the papers named here are referred to in the text ; a few are not specifi- 

 cally alluded to but were consulted during the work. Those marked * have not 

 been seen in the originals. 



*BRAUN, A., 1851. Verjung. i. d. Natur., p. 170, fig. 43, b-k. 



BRAUN, A., 1855. Algarum unicell. gen. nova et minus cog., etc. Lipsiae. 

 * BRAUN, A., 1886." Uber Chytridiuni, etc.," Abh. der konigl. Akad. d. Wissensch. 



zu Berlin. 



BRUNNTHALER, J., 1915, in Pascher, Siissw. Flora, vol. v, p. 180. 

 CHODAT, R., 1897. (a) " Algues pelagique nouvelle," Bull, de 1'Herb. Boiss., vol. v, 



p. 119. 



CHODAT, R., 1897. (b) " Etudes de Biologic lacustre," ibid., p. 289. 

 CHODAT, R., 1904. " Quelques points de nomen. algolog : 1. Sphaerocystia 

 Chodat, on Gloeococcus A. Braun," ibid., vol. iv (2me. ser.), p. 233. 



