368 SUMMARY OF CURRENT RESEARCHES RELATING TO 



colours the water a yellow chocolate-brown. He gives the quantitative 

 analysis according to Kolkwitz's methods. In some water in the 

 Botanical Garden at Lund, he records plankton-formation of about 

 500,000 per c.cm., of which T. volvocina was present in a proportion of 

 160,000 per c.cm., and Chrysococcus porifer Lemm. was twice as plentiful. 

 The other organisms were in smaller quantity. The principal colouring 

 agent was T. volvocina. 



Algal Flora of Traunstein and the Chiemgau.* — P. E. Kaiser 

 publishes an account of the algal flora in the neighbourhood of Traun- 

 stein and the Chiemgau in south-east Bavaria. This first list records 

 173 species and varieties, of which 44 are new for Bavaria. Very little 

 has been known of the algae and plankton of that district. 



Diatoms of Surian.f — P. Greguss describes the diatoms from two 

 mountain tarns, the " Meerangen," of the Siebenburg Alps of Kudsir. 

 They lie at a height of 1800 m. and 1900 m. respectively. Some years 

 ago 156 species, including three new ones, were collected from one of 

 the tarns and worked out by Quint ; they are published for the first time 

 in the present paper. From the other 187 species are recorded, 67 being 

 new. Of these two collections only 19 ■ 2 p.c. are common to the two 

 tarns. The species are principally Alpine in character. It is an in- 

 teresting fact that 95 p.c. of the bottom of one tarn consists of diato- 

 maceous material, considered by J. Pantocsek to be fossil. An opinion 

 of Scherffel's is quoted to the effect that the Echinopyxa are probably 

 cysts of Chrysomonads. 



Tetracyclus.J — F. Hustedt writes some critical studies on the struc- 

 ture and systematic arrangement of known forms of the genus Tetra- 

 cyclics. In the first part he gives the history of the genus, with its 

 synonyms and the diagnostic characters. The second part contains the 

 systematic account. The species have great power of variation, especi- 

 ally T. ellipticus Grun., to which the author pays special attention. 

 Diagnoses of the species are given, with complete synonymy, habitat, 

 and distribution ; also a key for the determination of the species. 



Russian Desmids.§ — A. J. Lobik records fifty-two species, with 

 varieties, of Desmidiaceae from the district of Cholm in the government 

 Pskow. Two new forms of species" are described. The paper is in 

 Russian, with a German resume. 



New 0scillariacea3.|| — G. Schmid writes on three new species of 

 Oscillariaceae, giving full accounts of their structure and comparing 

 them with already known species. Important notes on other species 

 are also given, and a figure of Oscillatoria numidica, hitherto unfigured. 



* Ber. Bayer. Bot. Gesell. z. Erforsch. d. Heini. Flora, xiv. (1914) pp. 145-55. 

 t Bot. Kozlemenyek, 1913, pp. 202-25 (with German abstract in Mitteil. f.d. 

 Ausland. p. 61) (2 pis.). 



X Abh. Nat. Ver. Bremen, xxiii. (1914) pp. 90-107 (1 table and 1 text-fig.). 

 § Bull. Jard. Imp. Bot. St. Petersbourg, xiii. (1913) pp. 65-86. 

 | Ber. Deutsch. Bot. Gesell., xxxii. (1914) pp. 122-30 (figs.). 



