ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 379 



as epiphytic on colonies of Gomphosphseria aponina, belong to M. 

 aeruginosa. The genus Sphinctosiphon of G-. S. West also belongs to 

 Microcystis. Anabsena fios-aquae f. discoidm Schmrdle is declared to be 

 a good species. Botryococcus Braunii Kiitz. is a variable species. The 

 author shows in a tabular form the relative frequency of the species at 

 each of the four stations visited by Borgert ; and contrasts Borgert's 

 results with those of Stuhlinann and Cunnington and with what is 

 known from Lake Nyassa. In a general summary the author states 

 that the great African lakes are distinguished by their proportional 

 richness in rare tropical species. The principal species in the two lakes 

 are the same ; of the 95 species 87 are common to both. But Nyassa has 

 24 species, and Victoria Nyanza has 34, which are respectively not 

 found in the other lake. The plankton of Tanganyika is very 

 different. 



Phytoplankton of the Aral Sea.* — C. H. Ostenfeld gives an 

 account of the phytoplankton of the Aral Sea and its affluents with 

 an examination of the alga3 observed. Except for an almost unknown 

 short paper by E. 0. Borszcow in 1877, this district has remained 

 untouched. The materials for the present report, 82 samples, were 

 collected by L. S. Berg's expedition in 1900-3. The list contains 19 

 Myxophycae, 6 Chlorophycae, 6 FlagellataB, 1 Silicoflagellata, 13 Peri- 

 diniales, 58 Bacillariales. The author describes nine new species and 

 makes critical remarks on older ones. He treats of the fresh-water 

 phytoplankton of the affluents Syr-Daria and Amu-Daria, and tabulates 

 the results obtained from them and from the Aral Sea itself. The 

 paper forms the eighth part of the scientific report on the Aral Sea 

 Expedition. 



Phytoplankton of the English Lakes.f — W. and G-. S. West report 

 on the phytoplankton of the English lakes. In an introduction the 

 authors refer to the important relationship which exists between the 

 geological character of a district and the constituents of its alga-flora, 

 more especially of its desmid-flora. They point out that the entire 

 Lake District is an Older Palaeozoic area, and that the really rich 

 alga-floras are all on Older Palaeozoic. The English Lake District 

 possesses a richer alga-flora than any other part of England, although 

 not quite equal to that of the north-west of Scotland or the west of 

 Ireland. The phytoplankton of the lakes is similarly rich in species, 

 although not so prolific as the limetic flora of the lakes of the north- 

 west of Scotland. In all, eighteen lakes were examined for their 

 phytoplankton, and detailed accounts of them are given. Moreover, a 

 general distribution table is appended displaying 135 species and 

 varieties of Chlorophyceae and 32 of Bacillarieae. 



Algae of the Yan Yean Reservoir.:}: — G. S. West has issued an 

 exhaustive report on the algae of the Yan Yean Eeservoir, Victoria, 

 which is of special importance, inasmuch as it constitutes the first 



* Isw. d. Turkest. Abteil. d. k. Russ. Geogr. Ges., iv. (1908) pp. 123-225. See 

 also Hedwigia, xlviii. (1908) Beibl., p. 102. 



t Naturalist, No. 626 (1909) pp. 115-22 (3 pis.) ; and No. 627, pp. 134-41. 

 % Journ. Linn. Soc. Bot., xxxix. (1909) pp. 1-88 (pis. and figs.). 



