Physiologie. — Algae. 3 



d'isoler le corps ou les corps cyanogenes des feuilles du Pangium 

 ediile, et ensuite de rechercher si elles contiennent de l'acide cyan- 

 hydrique franchement libre. 



II resulte de ces recherches que le glticoside existant dans les 

 feuilles du Pangium est identique ä la gynocardine (constate par 

 ses constantes physiques et par celles de l'acetate de gynocardine). 



Apres un examen special, dont les methodes chimiques ne peu- 

 vent etre relevees ici, l'auteur constate que la plus grande quantite 

 de CAzH , qui se trouve dans les feuilles y est ä l'etat libre et qu'il 

 n'est pas possible de decider avec certitude si eile est accompagnee 

 ou non d'une petite quantite d'acide faiblement fixe, lie ä un alde- 

 h3'de ou ä une cetone sous forme d'une cyanhydrine. 



T. Weevers. 



West, G. S., The Algae of the Yan Yean Reservoir, Vic- 

 toria: a Biological and Oecological Study. (Journ. Linn. Soc. 

 London. XXXIX. Bot. 6 plates, lO^figs. p. 1-88. 1909.) 



This paper is an exhaustive report on the Algae of the Yan 

 Yean Reservoir in Victoria, Australia, and constitutes the first 

 plankton-investigation of Australian waters. The reservoir in question 

 has a superficial area of about 1460 acres and is distant about 25 

 miles from Melbourne. In an Introduction to this paper, the author 

 gives an account of the water-supply, and the drainage area together 

 with a list of the plants found in the region, both spermaphytic 

 and pteridophytic. A map of the reservoir is given, shewing the 

 line of plankton collection. The paper is divided into several chapters, 

 of which the first three deal respectivelj^ with the phytoplankton of 

 the Yan Yean Reservoir, the littoral Alga-flora, and the general 

 Alga-flora of the drainage area. The Algae of the entire area, and 

 the different parts of it, are then discussed in their various relation- 

 ships; the more important and inieresting species are dealt with 

 systematically; and last]3^ attention is drawn to the peculiarities of 

 the Alga-flora of Australasian freshwaters. Samples of the plankton 

 were taken by boat at regulär monthty intervals for thirteen months, 

 in addition to samples from the weedy margin of the reservoir and 

 from various parts of the drainage area. The results of the author's 

 examination of the material are summarised by himself with much 

 lucidity. 



The phytoplankton of the Yan Yean Reservoir is rieh both in 

 number of species and individuals. It reaches its greatest develop- 

 ment in March and April, and is poorest in September and October, 

 in which months it is almost absent. It does not contain many 

 Flagellates, and remarkably few Myxophyceae ; while Cerathan Hirun- 

 diuella is completely absent, though it occurs in water which sup- 

 plies the greater part of the Yan Yean. The Yan Yean has a rieh 

 Desmid-flora, containing many characteristic Australasian types, in- 

 deed from February to April it consists almost exclusively of De- 

 smids. In the richness of its Desmid-flora the Yan Yean Reservoir 

 compares very well with the lakes of the western British lake-areas: 

 and it furnishes another instance of a rieh Desmid-plankton occur- 

 ring in a lake situated on the Older Palaeozoic formations and 

 receiving the drainage from extensive outcrops of these old rocks. 

 In the complete absence of Fragilaria and Asterionella, and of the 

 stardispositions of the frustules of Tabellaria, the phytoplankton dif- 

 fers conspicuously from the European plankton, but agrees with the 

 known plankton of the great African lakes. 



