ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 451 



Lower Forms of Chlorophycese.* — R. Gerneck describes a certain 

 number of lower algte belonging to Chlorophycefe, which he has been 

 able to isolate from a series of cultures. The material from which the 

 cultures were formed was collected from the neighbourhood of Gottingen. 

 The author describes the composition of the cultivating media, and the 

 manner of isolating the respective alga3. New species were discovered, 

 and these are described in detail in the first part of the paper, as well as 

 many other species previously known which were cultivated with great 

 success. The second part consists of general remarks bearing on the 

 result of the experiments. The cultures were naturally found to be 

 highly dependent on external influences, such as light and temperature, 

 as well as on the cultivating medium. The result of experiments in 

 media of high concentration is described ; and the growth of filamentous 

 forms, formation of gelatin, size and structure of the cell, reserve material, 

 resting cells, involution cells, and swarm spores, are all discussed. 



Phytoplankton of Warm Seas.f — B. Schroder describes some col- 

 lections of phytoplankton from the tropical and sub-tropical regions of 

 the Atlantic, Indian, and Pacific Oceans, as well as from the Mediter- 

 ranean. The results are presented in tabular form according to their 

 locality. Then follow critical remarks and diagnoses of new forms, 

 accompanied by many text figures. Finally the author gives a general 

 summing up of our knowledge of the warm phytoplankton, based on 

 previous work of other authors, and on his own results in the present 

 collection. He describes the phytoplankton of warm water as being 

 principally " polymiktes," consisting of many forms, and but few in- 

 dividuals ; only occasionally can a flora be described as " monotonous." 

 Instances of this occur in the Red Sea where Trichodesmium erythraum 

 predominates, and in the Mediterranean Halosphce-ra viridis. Lists are 

 then given of the characteristic species of : (1) Warm Atlantic and 

 Mediterranean ; (2) Indo-Malay seas ; (o) Western Pacific (S. and E. 

 China Sea and Japanese waters). Note is made of certain cold-water 

 forms whicli occur with various modifications in warm seas. 



Plankton of Eastern Alps.J— V. Brehm and E. Zederbauer publish 

 a general summary of their investigations into the plankton of the lakes 

 of the Eastern Alps, details of which have already appeared in the 

 Verhandl. k. k. Zool. Bot. Gesell. Wien. As regards the phytoplankton, 

 that of the lakes of the higher Alps is very poor both in species and 

 individuals. Of the eleven lakes mentioned, situated between altitudes 

 of 1260-2500 m. above sea-level, and only visited once a year, there 

 are four in which no plankton was found, and three in which only 

 filamentous algse {Zijgnema, Spirogijru) occurred. In the remaining 

 lakes the composition of the plankton varied much. The plankton of 

 18 other lakes at a lower elevation was found to be much more uniform 

 in composition. The principal constituents in winter are AsferioneUa 

 graciUima and Fragilaria crotoneiisis, and in summer Geratium Hirundi- 

 nella. These are typical for all the larger alpine lakes. As regards 



* Beih. Bot. Centralbl., xxi. (1907) pp. 221-90 (2 pis.), 

 t Vierteljahr. Naturf. Ges. Zurich, li. (1906) pp. .319-77. 

 X Arch. Hydrobiol. u. Plauktonk., i. (190G) pp. 469-95. 



