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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 GUnodinium 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 GUnodinium 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 Algce , 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 unfit 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. Pouch et 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. Yol. 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 divergent and P. ggolyedricum. 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 authors conclude that the number of individuals found 
in the viscera of one specimen is no less than 20 millions. Ike facts 
recorded by Pouchet & Guerne show that the Peridinia are not injurious 
to fish as a food. 
