Algae. — Eumycetes. 555 



The Schisophyceae occurring in marine plankton are few, and 

 the true marine plankton species are mainly restricted to the tropi- 

 cal and subtropical waters; one of them, Trichodesmium sp., probably 

 T. Thiehautii Gomont, reaches as far North that it occurs fairly 

 regularly in the summer at the mouth of the English Channel. 



Besides the true marine plankton species some brackish water 

 plankton species of Schisophyceae are found, and they are of im- 

 portance for the plankton of the Baltic Sea. The two most impor- 

 tant species are Aphanisomenon ßos aquae and Nodularia spumigena. 



Aphanisomenoyi is really a fresh water plankton organism, but 

 it is carried out by the rivers etc. into the Baltic, where it is 

 numerous and prominent in the true Baltic and the two Gulfs; 

 fairly common, but not in quantity, in the Belt Sea; and verj^ 

 rare and scattered in the Great Belt and the Kattegat. Its 

 flowering time is the late summer and autumn, but it is found in 

 the plankton the wole year round owing to the great floating 

 powers of the threads. Probably all the specimens carried out into 

 the sea die during the cold season without forming resting spores 

 (resting spores are not found in the sea), and every year a new 

 Invasion must take place from freshwater. 



With regard to Nodularia the biology is somewhat different; it 

 is a brackish water form which occurs on the bottom of slightly 

 Salt bays and inlets and is at times carried up into the plankton; 

 it reproduces itself vegetatively in the plankton, but dies away 

 every year, and a yearly new supply is thus necessar3^ Its distri- 

 butiön "in the Baltic is about the same as that of Aphanisomenon ; 

 also the time of occurrence. 



Anabaena baltica ]o\\s. Schmidt, another brackish water plankton 

 organism, but of less importance, has the same Liology ^iS Nodu- 

 laria: it is distributed from the Gulf of Finland southwards to 

 the Belts. Author's abstract. 



Chifflot. Sur l'extension du Marsonia rosae dans les cultu- 

 res de Rosiers. (C. R. Ac Sc. Paris CLXI. p. 336—338. 27 

 juillet 1914.) 



Le mycelium n'est pas exclusivement subcuticulaire. II s'etend 

 dans le parenchyme. Le parasite apparait des le mois de juin. II 

 envahit, non seulement le limbe, mais toute la feuille, la tige et 

 meme la fleur. II semble devenir vivace et capable d'envahir les 

 bourgeons qui servent ä la greffe. On doit brüler les feuilles tom- 

 bees et instituer un traitement preventif energique ä l'aide des 

 bouillies cupriques. P. Vuillemin. 



Coupin, H., Sur une Levure marine. (C. R. Ac. Sc. Paris. CLX. 

 p. 251—252. 15 fevrier 1915.) 



Torula marina n. sp. a ete rencontre entre les valves d'une 

 huitre portugaise vivante. Elle mesure 2— 3;U de diametre. Elle 

 pousse abondamment sur les milieux sales ou non, tres abondam- 

 ment sur carotte. La fermentation ne degage pas de gaz, mais 

 produit des acides avec glucose, levulose, galactose, Saccharose, 

 maitose, lactose, glycerine, mannite. Les colonies sont blanches. 



P. Vuillemin. 



Demelius, P., Beitrag zur Kenntnis der Cj^stiden. VII. 



