OF THE THIRD TANGANYIKA EXPEDITION. 83 
Phormidium, and Oscillatoria were very well represented, and eleven species 
of various genera have been regarded as new. 
The collections were preserved in formalin, and taken as a whole the 
material was in very good condition for examination. 
Considering the somewhat special character of the plankton, and the fact 
that it constituted one half of the material collected, I have dealt with it 
separately in the next chapter. 
The principal publications on Freshwater Algze from Tropical Africa, 
which are particularly important in conjunction with the present paper, are 
the following :— 
Е. Coun: Desmidiacee Dongoenses. Festschr. d. naturf. Ges. in Halle, 1879. 
С. F. О. Ховозтерт: De Algis et Characeis, I. Act. Univ. Lund. xvi., 1880. 
—— Conjugate. Forschungsr, S.M.S. ‘Gazelle,’ IV., Berlin, 1888. 
E. ре WILDEMAN: Quelques mots sur la flore algologique du Congo. Bull. Soc. roy. 
bot. Belg. xxviii. 2, 1889. 
J. B. De Том: Alge Abyssiniem a cl. Prof. О. Penzig collecte. Malpighia, Ann. v., 
fasc. vii.-ix., 1862. 
G. v. LAGERHEIM : Chlorophyceen aus Abessinien und Kordofan. La Nuova Notarisia, 
ser. 4, 1893. 
W. Wzsr & G. 5. West: A Contribution to our Knowledge of the Freshwater Algw 
of Madagascar. Trans. Linn. Soc. ser. 2 (Bot.) v. part 2, 1895. 
Alge from Central Africa. Journ. Bot. xxxiv. 1896. 
—— ——-  Welwitsch's African Freshwater Algæ. Journ. Bot. xxxv. 1897. 
W. 5снмїргє: Die von Professor Volkens und Dr. Stuhlmann in Ost-Africa gesam- 
melten Desmidiaceen. Engl. Bot. Jahrb. xxvi., 1898. 
——  Beitrüge zur Algenflora Afrikas. Engl. Bot. Jahrb. xxx., 1901. 
——  Sehizophyces, Conjugate, Chlorophycee in A. Engler, Die von W. Goetze am 
Rukwa- und Nyasa-See etc. ges. Pflanzen. Engl. Bot. Jahrb. xxx., 1902. 
— Algen, insbesondere solche des Plankton, aus dem Nyassa-See und seiner 
Umgebung, gesammelt von Dr. Fülleborn. Engl. Bot. Jahrb. xxxii., 1903. 
— Das Chloro- und Cyanophyceenplanhton des Nyassa und einiger anderer inner- 
afrikanischer Seen. Engl. Bot. Jahrb. xxxiii., 1904. 
О. MLLER: Berichte über die botanischen Ergebnisse der Nyassa-See und Kinga- 
Gebirgs-Expedition, VII. ВасШамасееп aus dem  Nyassalande und einigen 
benachbarten Gebieten. Engl. Bot. Jahrb. xxxiv., 1905; xxxvi., 1905. 
П. THE PHYTOPLANKTON. 
General remarks.—The observations on the phytoplankton of Lake Nyasa, 
Victoria Nyanza, and Lake Tanganyika are largely concerning the occurrence 
of certain species, and it has been a matter of no small difficulty to identify 
with certainty some of these plankton-forms. With regard to the. species 
which were present in the collections, the examination of the material has 
been fairly exhaustive, but owing to the restricted explorations little can be 
said about the periodicity, or concerning any maximum development which 
these species may attain. In Lake Nyasa the material was collected in 
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