216 SUMMARY OF CURRENT RESEARCHES RELATING TO 



the analysis of the plankton cannot be made in one operation ; but two 

 are necessary. For when, by the proper method, the diatoms are 

 stained, the Peridinieas remain colourless ; and vice versa. For the 

 Peridiniege Mangin employs iodised fuming hydriodic acid, followed 

 by glycerinated chloral ; the Peridiniege become violet-brown and the 

 diatoms are almost invisible. The operation can be completed by 

 double staining with " azobleu," " azoviolet," or " azurine brillante." 

 For the diatoms such stains as safranin, methylen-blue or old alum- 

 hasmatoxylin may be used. Further stains and details of manipulation 

 are described. 



Methods of Plankton Research.* — W. J. Dakin publishes an 

 account of the methods of plankton research, in which he describes and 

 figures the construction of plankton nets, and describes the method of 

 using the quantitative net ; the preservation of the catch ; the estima- 

 tion of the catch ; the pump, tube, and filter method ; the method of 

 investigation for the smallest organisms, as by the Kriimmel water- 

 bottle ; other plankton apparatus used for qualitative work, as the 

 Brutnetz, the Scherbrutnetz, the Kntippel net, the Plankton Rohre. 

 And he gives an account of some results of the plankton work and of 

 its aims, and concludes with a bibliography. 



Marine Flora of Inland Salt Marshes.")"— M. Gomont publishes a 

 preliminary note on the marine algee of Lorraine, that is, on the algfe 

 which inhabit the salt marshes near Nancy, in the valley of the Seille, 

 etc. Remote as the district is from the sea-shore, it exhibits a strong 

 growth of Lyngbya sestuarii and Microcoleus chthonoplastes, which are 

 characteristic of salt-works situated on the sea-coast. The list contains 

 forty-six species and varieties. Owing to natural and artificial causes 

 the degree of salinity of the water varies much and often. How the 

 algae have reached their inland situation is not discussed in the present 

 paper. 



Phyllosiphon Arisari.J — R. Maire makes some remarks on a 

 parasitic alga (Phyllosiphon Arisari Kiihn), which, in the Mediterranean 

 region, occurs frequently during winter and spring on the leaves of 

 Arisarum vulgare, forming yellowish-green to yellow spots, ^-1 cm. in 

 diameter. The filaments of the alga occupy the intercellular spaces and 

 hinder the development of the chloroplasts ; hence the yellow-green 

 colour of the spots affected. Then the parasite provokes the secretion 

 of yellow-orange oleaginous droplets in the cells of the host-plant ; 

 hence the spots turn yellow. Finally the leaf withers, the oleaginous 

 droplets disappear, and the filaments of Phyllosiphon, now packed with 

 green aplanospores, render the affected spots strikingly green on the 

 colourless withered leaf. The same alga was found by Maire on 

 Arisarum simorrhinum at Oran, in Algeria, and recently on Arum 

 maculatum, near Luneville, in France. Whether in the latter place it 

 is natural or introduced, remains to be proved. 



* Proc. and Trans. Liverpool Biolog. Soc, xxii. (1908) pp. 500-53 (figs.). 



f Bull. Soc. Bot. France, lv. (1908) pp. xxix.-xxxiii. \ Tom. cit., pp. 162-4. 



