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common oyster , and the large fresh-water muscle. 
oysters should, by common consent, be admitted neither to 
be good nor wholesome, under the same circumstances ; for 
no general law against dredging for them would prevent 
those possessed of private beds from indulging their appetites 
during the months of May, June, and July, if they found that 
oysters were better in those months. 
I had an opportunity last July of setting this question at 
rest; for being at Dieppe, in France, where there is no 
restriction laid upon oysters, I ordered some for dinner : they 
had no flavour, none of the company could eat them. I found 
it equally true in Paris ; but the fact is, the period respecting 
the oyster, which corresponds to the breeding season of fishes, 
is March and April, when the ova are getting ready for im- 
pregnation. In June and July the ova have been impregnated, 
and may be said to have spawned at the time the embryo is 
first received into the oviduct, which is in the month of June. 
At the time the young oysters leave the oviduct, there is a 
mucus of a purple colour which is voided at the same time, 
probably for the purpose of supplying them with nourishment 
while they remain enclosed within the enveloping mantle by 
which the gills are surrounded. 
While in this situation they often become a prey to small 
sea-worms, which get between the shells, and gorge them- 
selves with the young ones. I have seen these worms with 
their stomach completely distended with young oysters. 
There are many curious structures met with upon the edge 
of the mantle which encloses the gills. As these appear en- 
larged in the breeding seasons, their uses may be applicable 
to the growth of the animal, of the shell, or the formation of 
nacre. Accurate representations of them are given, that others 
