ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 329 



Potamoplankton.* — Y. Brehin publishes some observations on the 

 origin of the potamoplankton of the River Eger, which is in its richest 

 condition when the patches of Oscillatoria are in their highest state of 

 development. The tributaries of the river have very little influence ; 

 the plankton is generated in such places as quiet bays, backwaters, 

 lakes, etc. 



Variability of PeridiniaB.t — L. Mangin discusses the modification 

 of the cuirass of certain Peridiniaj. It alters considerably during life, 

 and he feels that the limits of its variability ought to be registered with 

 a view to the proper limitation of species. 



Prowazekia.J — E. R. Whitmore describes Prowazekla asiatica, one 

 of the Flagellatse — its shape, cytoplasm, nuclear structure, blepharoplast, 

 propagation, and resting stage. The species differs from P. parva in 

 size and in the retention of its cilia during the resting stage, and from 

 P. parva and P. Cruzi in the fibrillar appai'atus connected with the 

 blepharoplast. It is synonymous with Bodo asiaticus Cast, and Chalm. 



Swiss Phytoplankton.§^H. Bachmann writes of the wine-red 

 water-bloom (Burgunderljlut) of the Rothsee, near Lucerne. He gives 

 a list of the phytoplankton observed in the Rothsee by Hool in 1907. 

 In March 1910 an enormous quantity of Oscillatoria rubescens made its 

 appearance in the water for the first time. If present previously it 

 must have been very small in quantity, and was overlooked. It may 

 have been introduced by birds. During the presence of this water- 

 bloom only three out of the forty recorded species were found in the 

 lake, and those in small quantity. 



New Plankton from Posen.|l — J. Woloszynska given an account 

 of some rare plankton algae collected at Posen, and describes two species 

 and two varieties which are new to science. 



Phytoplankton of Fresh-water.iT — H. Bachmann gives an account 

 of fresli-water phytoplankton, with special reference to the Vierwald- 

 stattersee (Lake of Lucerne). Finding that there is no single work of 

 reference to which a student may turn for a complete account of the 

 phytoplankton of fresh-water, he has brought together and condensed in 

 the present volume the work of all previous authors on the subject. 

 Thus he gives a diagnosis of every species, with many critical notes, 

 keys to the species, much original work of his own, discussions of 

 abnormalities and variations, with copious figures. He treats of the 

 four big groups separately : Flagellataj, Diatomacese, Conjugatae, Cyano- 

 phycege. He describes the methods of capture of the material and the 

 nets and apparatus employed. In his bibliography he cites 191 papers. 

 In a later volume he will treat of the general biological questions that 

 concern fresh-water plankton. 



* Intemat. Rev. gesammt. Hydrobiol. u. Hydrogr., iv. (1911) pp. 311-14. 

 t luternat. Rev. gesammt. Hydrobiol. u. Hydrogr., iv. (1911) pp. 44-54 (2 pis.). 

 X Arch. Protistenk. Berlin, xxii. (1911) pp. 370-6 (1 pi. and figs.). 

 § Naturw. Wochenschr.. n.f. ix. (1910) pp. 602-4. 

 11 Bull. Internat. Acad. Sci. Cracovie (1911) pp. 265-6. 



^ Das Phytoplankton des Siisswassers. Jena ; G. Fischer (1911) 218 pp. (15 

 col. pis. and tigs.). 



June 19th, 1912 2 A 



