ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 589' 



supply is pumped up straight from the Moldau into reserYoirs, whence 

 it flows to the houses. Two classes of organisms were found : (1) deYe- 

 loped in the water-pipes ; (2) deriYed from the ]\roldau, the flora of 

 which is known. The first includes such forms as Lcptothrix. Crenotlirix, 

 Cladotlirix, GlonotJtrix, etc. The second includes principally plankton, 

 namely, 10 Flagellat^e, 5 Pei'idiuea3, 16 Diatomacea3, ;>J: ChlorophycefB 

 with Conjugate, and 4 Schizophyce^e. Physiological obserYations are 

 made upon some of these. As regards the periodicity of the species, the 

 author points out that some of them, such as Sijiiedra Ulna, predominate 

 in the spring, and others in the autumn, for instance, Melosiragraiiulata ; 

 but most of them are summer forms, and in winter there is a dearth 

 of both species and- indiYiduals. And this periodicity corresponds with 

 that of the Moldau aboYe Prague. The bacteria {Bacterium coli and 

 others) are more abundant in winter than in summer. A new water 

 supply is projected. 



Phytoplankton of the Traun-see.* — K. von Keissler has examined 

 the phytoplankton of this lake, situated in Upper Austria, and found the 

 total amount of plankton here to be very small, just as in the Hallstiitter- 

 see. As regards quahty, it is poor in species, at times consisting of one 

 species only, AsterioneUa. The neighbouring larger lakes are much 

 richer in species. The poverty of quality and quantity in the Traun-see 

 may be due to the relatively low temperature of the water even in 

 summer. The Flagellatas are almost entirely absent ; the Peridinefe 

 and Chlorophycefe are represented by one species each ; and the principal 

 constituent is formed by the Diatomacete. The results are presented in 

 the form of tables, followed by a list of species. 



Algae of the Kossogol Basin. f — C. H. Ostenfeld reports on the 

 phytoplankton and other alga? of the Kossogol Lake in North-West 

 Mongolia, and of the ponds and rivers in the immediate neighbourhood, 

 collected by Elpatiewsky. The collection consisted of 50 samples of 

 plankton and some of mud. The author's principal object was to study 

 the composition of the phytoplankton, and secondarily to determine the 

 other algte ; and he does not profess that the present list is at all 

 exhaustive, especially as regards the Desmidiacese, which in any case are 

 not well represented. His results are divided into two main divisions : 

 (1) a systematic enumeration of the 90 species observed, with habitat, 

 and critical notes ; (2) considerations concerning the phytoplankton of 

 Kossogol and the surrounding waters, together with comparisons with 

 each other and with other regions. These are followed by a review of 

 all literature dealing with the algre of this part of Asia as well as remarks 

 on the geographical and hydrographical conditions of Kossogol ; and 

 finally by a list of the samples arranged with a running number and in 

 chronological order. An appendix contains the list of species in each 

 sample. As the result of the author's examination, he finds that Lake 

 Kossogol itself possesses but a poor phytoplankton, the character of 

 which is markedly alpine, the species being for the most part those 

 peculiar to the Swiss lakes. Both species and individuals are few, and 

 the diatoms are without special interest. The characteristic species are 



* Oesterr. Bot. Zeitschr., Ivii. (1907) pp. 146-52. 



t Hedwigia, xivi. (1907) pp. 365-420 (1 pi. aud 1 map). 



