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weather had been stormy the organism would have been more 

 diffused, and consequently might have been less injurious, and it 

 might possibly have remained unnoticed. 



The destructive effects brought about by the Glenodinium are 

 difficult to account for. As far as the family Peridiniidce is 

 concerned there does not appear to be any valid reason why 

 they should be regarded as injurious when taken as food,* their 

 chemical constituents are similar to what is found in diatoms, 

 desmids, and many other minute forms of life which are known 

 to provide a highly nutritious food for oysters, mussels, and other 

 lower forms of animal life. Several samples of highly discoloured 

 water were obtained from different localities and at some distance 

 from the shore, with a view to ascertain if the Glenodinium gave 

 off any fcetid odour, such as is often the case with water in which 

 there exists living organisms in large numbers — particularly 

 fresh water containing Peridinia, unicellular Alc/ce, and other 

 forms rich in protoplasm — but I could not detect any unpleasant 

 smell in the water examined. At several places where the 

 organism existed in great abundance, I collected some of the mud 

 by carefully skimming the surface with a spoon in order to 

 determine if its death and subsequent decay had anything to do 

 with the fouling of the water, but I failed to find any evidence 

 that such was the case either in the mud or in the water. If the 

 organism is not in itself injurious when used as food, and it does 

 not affect the water by its death and decay, how has it acted so 

 injuriously on the shore fauna 1 This is a question that could 

 only be satisfactorily answered by a long series of experiments. 

 After giving the matter serious attention, and making a careful 

 examination of a number of the oysters and mussels, I am of the 

 opinion that they died from suffocation brought about by the 

 presence of vast numbers of the organism in question. It is very 

 evident that water so thickly charged with millions of minute 

 forms for a period of six weeks in succession would be untit to 

 support life in a healthy condition, and even if only a small 

 percentage of the oysters, mussels, and other forms were killed 



* Since the above remarks were written, 1 have seen a paper by MM. 

 G. Pouchet and J. de Guerne, " On the Food of the Sardine " (Comptes 

 Rendus, 1887, p. 712), an abstract of which is given in the Ann. & Mag. 

 N. H. Vol. xix. 5 ser. 1887, p. 323. The authors, after enumerating some 

 of the organisms constituting the food of the sardine, go on to state that 

 " The chief interest of the viscera from La Corogne is the extraordinary 

 abundance of Peridinians which fill them. These belong to two types, 

 Peridinia divergens and P. polyedricum. The latter literally fills the 

 digestive tube of the sardines, being recognizable even in the rectum." 

 After estimating the cubical capacity of the intestine and the size of the 

 Peridinium, the aiithors conclude that the number of individuals found 

 in the viscera of one specimen is no less than 20 millions. The facts 

 recorded by Pouchet & Guerne show that the Peridinia are not injurious 

 to fish as a food. 



