48 
time of my visit (July 3rd and 4th) which was just the 
period when the free-swimming embryos were settling 
down, the water over the parcs seemed to be swarming 
with them, and the spat was making its appearance all 
over all sorts of suitable submerged objects. 
The great importance of Arcachon in oyster culture is 
undoubtedly as a place where the adult oysters reproduce 
freely, and where the free-swimming larve or “‘fry’’ when 
settling down as spat can be readily collected and so be 
saved from destruction and made available for artificial 
rearing. The oyster chiefly cultivated at Arcachon is 
Ostrea edulis the ordinary rounded flat oyster of Northern 
Europe, but the large elongated Portuguese oyster, Ostrea 
angulata, is also abundant at Arcachon and is said to be 
increasing. There was some alarm recently amongst the 
oyster proprietors upon the ground that these two species 
were breeding together and producing an inferior kind of 
hybrid. This fear has however been dispelled, as it is well 
known to biologists that the reproductive arrangements 
in the two species are very different. A much more 
practical, and in fact quite likely, difficulty would ensue 
if the Portuguese oysters became so numerous in the 
“bassin,” that their fry would come into competition 
with the fry of Ostrea edulis in settling down on the 
‘“‘ collectors,” and being, it is said, more hardy animals 
would oust the latter is the struggle for existence. 
The oyster reproduces at Arcachon between May and 
the beginning of July and the young animal leads a free- 
swimming existence for nearly a week before settling 
down. The cultivators (‘‘ parqueurs’’) examine carefully 
the condition of the spawn in the old oyster and at what 
they consider to be the proper time (generally about the 
end of June) for catching the deposit of spat, or young 
oyster ssettling down after the free-swimming existence, 
