834 REPORT OF COMMISSIONER OF FISH AND FISHERIES. [10] 
not yet attained one-fifth the size necessary for them to break their cap- 
sule and pass into the oviduct; and that they require fifteen days to: 
attain this size, without this latent fecundation showing itself by any 
appreciable sign. 
Under parallel circumstances artificial fecundation, such as is prac 
ticed among fish, would be impossible; for, to procure eggs, it would be 
necessary to forcibly extract them from the midst of the torn ovary, and 
thus remove them from their normal condition. With oysters, the im- 
possibility is still more evident; the eggs and spermatozoa, originating 
in the tissues of the same organ, could not be extracted and separated 
from each other in such a manner as to permit of their being afterward 
united in one vessel. Besides, even in case this operation should prove 
successful, it would be necessary to place the artificially-fertilized eggs 
in a suitable medium; and where could this medium be found except 
within the mantle of the female? 
Thus, in whichever way we consider the question, we must arrive at 
the conclusion that with oysters the natural processes are the only prac- 
ticable ones and the only ones we ought to advise for this industry. 
We shall come to see, in treating of the breeding of oysters at Marenne, 
what advantage the culturists of that locality would be able to derive | 
from the employment of the processes applied in Lake Fusaro. 
B.—GREEN OYSTERS OF MARENNE. 
The reservoirs in which the culturists of Marenne deposit oysters in 
order to give them a green color bear the name of claires. They are like 
so many inundated fields distributed here and there upon the shores of 
the Bay of Seudre, and spread over several leagues of space, forming 
an immense domain. Here there is carried on a curious and lucrative 
trade, the development of which is favored by the State by concessions 
made to enrolled seamen who wish to devote themselves to this kind of 
business. 
These claires differ from the fish ponds and ordinary parks in that 
they are not submerged at each tide like the latter, but only at the pe- 
riods of the high tides, which occur with the new and full moon, when 
the waves reach higher upon the land than at other times; too frequent 
submersion would be an obstacle to the end proposed. They are, con- 
sequently, not established on the immediate borders of the sea-shore, as 
certain authors have erroneously supposed. 
Those which are most favorably situated receive water two or three 
days before and after the high tides; but that depends upon their rela- 
tive distance from the shore. In this way the water they contain is 
never entirely renewed, or, if there is a complete renewal, it takes place 
only at considerable intervals of time. These intervals cannot, how- 
ever, exceed the period intervening between the epochs of the spring- 
tides without serious inconvenience to the industry; for experience 
