156 . Protozoa. 



and consists of enlarged cells containing bacteria; and (4) the basal zone, containing 

 cells filled with oil drops. After the nodules are fully developed the bacteria disappear, 

 and in old nodules mycorrhiza filaments are found. 



Pure cultures of the bacteria showed that they were identical with Pseudomonas 

 radicicola. 



Young iJ/^/^-tca-plante grown in sterilized nitrogeu-poor soil did not flourish, but after 

 inoculation with the bacteria, developed nodules and grew well. Gates (London). 



4-2'7) Spratt, Ethel R. (London, King's College), The morpliology of the 

 root tubercles of Alnns and Elaeagnus and the polymorphism of 

 the organism causing their formation. In: Annais of Botany, Bd. 26, 

 Heft 1, S. 119—128, 1912. 



It is found that Pseudomunas radicicola, the bacterium in these root- 

 tubercles, propagates itself in the cortex of the nodule as a rod-shaped organism, 

 which in Elaeagnus produces a zoogloea. Later, large spherical bodies are found 

 in the cells, which multiply and fill the cell until they finally "lose their identity 

 and a group of bacilli remain in their place". These spherical bodies are believed 

 to represent a coccus form of the same organism, which is believed to be "cor- 

 related with scarcity of available carbohydrate and change of environment". 



In Elaeagnus the nuclei of the host plant undergo some change under the 

 influence of the zoogloea. It is concluded that the presence of the organism is 

 undoubtedly beneficial to the plant. Gates (London). 



428) Dale, Miss E. (Cambridge, School of agriculture), On the cause of "blindness" 

 in potato tubers. In: Annais of Botany, Bd. 26, Heft 1, S. 129—131, 1912. 



The destruction of the "eyes" or buds of jjotatoes is caused by the mycelium of 

 a fungus, Vcrticülium albo-atrum. This fungus produces new infections without the 

 means of spores, by growing along the subterranean shoots, internally as a colorless 

 mycelium in the cortical tissues, and externally as a scanty brown mycelium. 



Gates (London). 



429) Dale, Miss E., A bacterial disease of Potato leaves. In: Annais of Botany, 

 Bd. 20, Heft 1, S. 133—154, 1912. 



A new bacterial leaf- disease of the potato is described, caused by Bacillus 

 tuhifex n. sp. The organism enters the leaves by piercing the cuticle where it is thin. 

 It forms a kind of zoogloea and dissolves the middle lamellae by means of an enzyme, 

 thus passing through cells and forming an "iufection tube". 



The organism was isolated and its behaviour in culture is described. These bacteria 

 are aerobic or anaerobic, can cause fermentation, and can live either as parasites or 

 saprophytes. This adds another to the known bacterial diseases of solanaceous plants. 



Gates (London). 



Protozoa. 



430) Herdman, "W. A., Dinoflagellates and Diatoms on the Beach. In: Nature 

 LXXXVI, 2173, 2 S., 1911. 



Am 7. April 1911 beobachtete Verf. eine briiunliehgrüne Verfärbung auf dem Sand- 

 strande bei Port Er in. Dieselbe wurde von der massenhaft auftretenden Peridinee 

 Amphidinium opcrculatum hervorgerufen. G. Stiasny (z. Z. Wien). 



431) Maugiii, L., Sur le Pcridiniopsis asymmetrica et le Peridinium Paul- 

 seni. In: C. li. Ac. Sc. Paris CLÜI, 5 S., 2 Textfig., 1911. 



Beschreibung zweier neuer Peridineenspecies: Peridiniopsis asymmetrica mit kon- 

 stanter Asymmetrie, hervorgerufen durch das Vorhandensein einer supplementären linken 

 Apikalplatte und einer rechten Platte in der Antapikalregion. Kein Diplopsalis, da 6 

 Prääquatorialplatten vorhanden sind (dort 5). — PeridiuiHm puuheni hat in der Apikai- 

 region 4 Apikaiplatten, davon 1 kleine linke supplementäre, ist verwandt mit P. cerasus. 

 Es werden auch Anomalien beschrieben. G. Stiasny (z. Z. Wien). 



