OYSTER AND MUSSEL REPORT. 73 
the case of Arcachon and of Les Sables d’ Olonne there is 
a sheltered inland sea, with a narrow entrance through 
which the tide runs in and out with a considerable cur- 
rent. The temperature of this water I found to be 66°F., 
and the specific gravity 1:025 to 1:026, practically that of 
the open sea. In this area there are oyster pares for élevage. 
No production of spat takes place here, the young oysters 
being mostly obtained from Auray, a little to the north, 
when about two years old and 5 or 6 cm. in diameter. 
The parcs contain abundant vegetation, the same green ° 
ales being apparently present as those I found at 
green’’ oysters are produced 
ce 
Marennes, and simular 
in some of the parcs, although they are perhaps not so 
well known as those from the estuary of the Seudre. 
I examined the parcs at Croisic at low tide, and photo- 
graphed one set of 12 quadrangular areas, each about 30 
yards by 15 yards, separated from one another by a double 
row of stakes supporting planks, the space between these 
palings—about 2 yards across—being filled in with mud 
and gravel. The stakes are placed about a yard apart. The 
parc contains about 2 feet of water and there isa sluice at 
one end of each enclosure. The walls between adjacent 
pares are of this great thickness (2 yards) because there is 
no stiff clay here like that which makes such excellent 
enclosures at Arcachon. Ambulances with wire net lids, 
like those at Arcachon, are also in use here for the very 
small oysters. There are also great salt and oyster-rearing 
excavations near to at Le Poulignen, and also between 
Le Croisic and Le Bourg-de-Batz as shown in the accom- 
panying sketch-plan (Pl. III, fig. 3). The more irregular 
areas shown in the left foreground and in the distance on 
each side of the watcher’s house are oyster pares, while the 
very regular areas in the centre are for the manufacture 
of salt. Mussels are also cultivated here both in beds and 
