ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 211 



In the open river AsterioneJla was most abundant, and, speaking 

 generally, the plankton of the Volga consisted mainly of diatoms. The 

 second chapter is devoted to a systematic account and geographical 

 distribution, together with descriptions of new species. The third 

 chapter contains a tabulated comparison of the plankton of the main 

 river, and that of ponds and other waters cut off from it. 



Plankton of the Elbe.* — E. Volk publishes his report on the 

 biological conditions of the Elbe and its tributaries in the neighbour- 

 hood of Hamburg. The paper deals with the animal life of the river 

 plankton, as well as the phytoplankton, which includes 159 species of 

 Chlorophyceas and of Rhodophyceaj, 267 of Diatornacete, and 45 of 

 Schizophycea3. The chemical composition of the water is discussed, and 

 the methods of work are described. An analysis of the phytoplankton 

 is presented in the form of a table showing the occurrence of each 

 species according to season and locality. 



Atlas of Diatoms.f — Heiden, of Rostock, has brought out the 

 61st fascicle of A. Schmidt's Atlas, comprising plates 241—4. Many 

 species of Stauroneis and Navicula are figured, belonging to the sections 

 humeroscc and granulate. Eleven new species are figured, as well as 

 some new varieties. 



Diatoms from the Jura.J — P. Prudent gives a list of diatoms collected 

 in two lakes of the Jura, Nantua and Silans. The flora of both are 

 very similar, and the total number of species amounts to 152. The 

 most interesting records are : — Gymbella Loczyi Pantocs., C. affinis 

 Kiitz., with an undulated dorsal margin, Galoneis rupestris var. inflate 

 Pantocs., Fragilaria muiabilis var. trinodis n.v., and Nitschia angustata 

 var. producta Pantocs. 



Cultures of Diatoms.§ — P. Miquel continues his researches into the 

 physiology, morphology and pathology of diatoms, and describes his 

 cultivation of Nitzschia linearis. After a successive series of ten cultures, 

 each new one being made from the last one, he found that the size of 

 the frustule diminished 17 /*, namely, from 115*2 /* to 98*1 /a. The 

 greater number of frustules contained in the ten cultures were of 

 medium size ; those showing either extreme in size were excessively 

 rare. The author notes that in Melosira and Gyclotella those individuals 

 which formed auxospores were far from being of the smallest size. 



Caulerpa anceps.|| — K. Yendo adds some interesting facts to our 

 knowledge of this alga. A plant was collected in Japan by Prof. Okamura, 

 and at first identified by him as G. brachypus Harv., but subsequently 

 corrected to G. anceps. K. Yendo found a plant on a small reef at 

 Misaki, in October, 1888, and identified it as G. br achy pus, but on the 

 same reef he found in summer G. anceps. Feeling doubtful whether 



* Julirb. Hamburg. Wissensch. Aristalt., xix. Beih. 2 (1903) pp. 65-154. 



f Atlas der Diatomaceenkunde, Leipzig, 1903J Heft. 61. See also Nuov. Xotar. 

 xt. (1904) p. 47. 



\ Contrib. a la flore diatomique des lacs de Jura, Lyon, 1903. See Nuov. Notar. 

 xv. (1904) p. 38. 



§ MicrograpbePre'parateur, xi. (1903) pp. 174-9 (figs, in text). 



|1 Bnt. Mag. Tokyo, xvii. (1903) pp. 153-7 (6 figs, in text). 



