OYSTER AND MUSSEL REPORT. 53 
Many of the oysters are sold at this stage to the 
“‘éleveurs’’ who rear and fatten them, but many on the 
other hand are kept for another year or two in the pares 
at Arcachon. These latter after removal from the tiles 
are placed in flat trays having a floor and a lid of close 
galvanized wire netting, of about half inch mesh, and these 
trays are placed between short posts in the sea on the 
oyster parc so that the tide can run freely through them 
supplying the oysters with food and oxygen. Such trays 
are called ‘‘ambulances’’ or ‘‘ caisses ostreophiles”’ and 
are shown in Pl. I, figs. 4,5. They measure about 6 feet 
by 4, and are 6 inches deep. They serve to keep the young 
oyster during the early period of its life out of the sedi- 
ment, and they also protect it from its numerous natural 
enemies, such as the boring sponge (Cliona) which ruins 
the shell, starfishes and crabs which manage to suck or 
pick out the soft animal, and whelks (such as Purpura 
and Nassa) and other Gastropods, which can bore a hole 
through the shell and prey upon the oyster. 
The ambulances are constantly looked after by the 
oyster men, and especially women, who come at low 
tide when the caisses are exposed, open the lid and pick 
over the contents, removing any enemies or impurities 
which may have got in, such as crabs, taking out any dead 
shells, and re-arranging the oysters if necessary so that 
all may have a fair chance of obtaining food and growing 
normally. The young oysters grow rapidly in the ambu- 
lances and have soon to be thinned out. The larger ones 
are removed to other caisses—or, if large enough, they 
are thrown into the open enclosures of the parc. Addi- 
tional young ones may now be added, or all the space may 
be required for a time by those left. In this way, by 
thinning out, re-arranging, and adding, relays of young 
oysters in their first year may occupy the ambulances for 
