OYSTER AND MUSSEL REPORT. Vt 
the same, the fauna both macroscopic and microscopic is 
not appreciably richer, and although the temperature of 
the water is certainly higher in the south, probably on the 
average about 10°F. higher, still I do not think that that 
is essential, and it may even be considered doubtful whether 
it is much advantage. The opinions of the practical men 
I met in France differed on this point. Mons. Dasté at 
Arcachon was convinced that considerable heat was 
absolutely necessary for the successful breeding of oysters, 
and that the greater the heat the better the deposit of spat. 
It is not unnatural for the successful breeder of oysters to 
be influenced—perhaps unconsciously—by the desire to 
keep that branch of the industry as much as possible in 
his own hands, and to think that the conditions found in 
his district are essential, and that all that should be 
attempted elsewhere is to rear the oysters he has pro- 
duced. In opposition to that opinion we have the facts 
that Capt. Dannevig has had oyster spat produced in 
abundance in his pond at Arendal in Norway, and that 
both on the north coast of France and the south coast of 
England oysters reproduce and spat is deposited. 
Lately Prof.H. de Lacaze-Duthiers has proved that even 
under artificial conditions in the aquarium of the Zoolog- 
ical Station at Roscoff on the North Coast of Brittany, he 
can bring seed oysters to a high state of development and 
commercial value, and that the oysters will reproduce in 
the aquarium, spat be deposited, and the young oysters 
be readily reared up until they are fit for the market—the 
entire life-history having been passed through in confine- 
ment. I consider that this is an important observation 
as there can be no doubt that under natural or semi- 
natural conditions a very large proportion of the free- 
swimming embryos are carried away by tides or currents 
and either destroyed or lost to the cultivator. 
