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formation of carbonic and organic acids, but without any production 

 of alcohol neither in the air nor in a hydrogen atmosphere. 



Destruction of the cellular structure and treatment with alcohol 

 or acetone do not therefore inactivate the respiratory enzymes in 

 the present case, their powder of decomposing sugar remains very 

 marked. 



In the same way a crude enzyme is obtained from the leaves of 

 Sauromatum, which is similar, but has a weaker action. 



In the ether extract of the acid liquid citric acid was demonstrated, 

 which acid very probably must be formed by the respiratory enzymes 

 at the expense of the glucose. 



Amersfoort, September 1911. 



Zoology. — " Pleistophora gigantea Thélohan, a parasite of Crenila- 

 hrus m.elops." By N. H. Swellengrebel. (Communicated by 

 Prof. Max Weber.) 



(Communicated in the meeting of September 30, 1911). 



Among the neosporidia the microsporidia distinguish themselves 

 by their spores, which are smaller than those of the allied myxo- 

 sporidia and do not possess such distinct polar capsule and polar 

 filament as the spores of the latter group. 



According to Minchin flQOS) the microsporidia are divided into: 



1. Polysporogenea ; the trophozoite (i.e. the vegetative generation') 

 forms many pansporoblasts, each of which contains many spores. 



2. Oligosporogenea; the trophozoite transforms itself entirely or 

 partly into one single pansporoblast. Each pansporoblast contains 4, 

 8 or many spores. 



The parasite that I wish specially to describe here has the following 

 life-history. Trophozoites with one or more nuclei are found in 

 the connective tissue of the skin and in the mesenteriuni of Creni- 

 labrus melops. After encystment the trophozoites form by successive 

 division an unequal number of sporoblasts, each containing two 

 nuclei. These sporoblasts become spores by the formation of a 

 thick membrane. The spores have one or two nuclei, whilst there is 

 nothing that points to the existence of a polar capsule with polar 

 filament. 



Thelohan (1895) described a microsporidium, Glugea gigantea, 

 found in the abdomen of Crenilabrus melops. He has not been able 

 to investigate the development of this parasite, but only states that 



