50 
water may flow readily in between and around them. 
The cases of collectors I measured were about 6 feet in 
length by 2 feet in breadth and 3 feet in height; each holds 
120 tiles arranged in 10 tiers or layers. The tiles in any 
tier are placed with their long axes at right angles to those 
of the tiers above and below, as is shown in PI. L,, fig. 2. 
This it is thought breaks up better than any other 
arrangement the currents of water as the tide runs through 
the ‘“‘ruche’’ and so gives the young oysters a better 
opportunity of affixing themselves to the tiles. This is 
the arrangement in the ‘ gabaret”’ collectors or ‘ tuilles. 
en ruche,’’ which is considered after numerous experiments 
to be the best form at Arcachon, but various other forms 
of tile collectors are in use elsewhere and are better suited 
to special local conditions, such as depth of water and 
softness of bottom. The tiles are always placed with the 
convex surface upwards as it is very important that there 
should be as little opportunity as possible given for the 
collection of any fine sediment in which the young oysters 
might be smothered. 
I was very fortunate in seeing some of the tiles just 
after the young oyster spat had been deposited, and one 
of the figures (Pl. I, fig. 3) represents Mons. Dubourdieu 
holding up such a tile, covered thickly with the little 
amber coloured specks, less than ;; inch across, for me to 
photograph. There may be several hundred such young 
oysters on one side of a tile. I had the advantage of going 
round with Mons. Peseux and Mons. Dubourdieu on July 
3rd, when they were inspecting their collectors, and they 
and also Mons. Dasté assured me that this was an especi- 
ally good year for spat. They attributed that to the con- 
tinued fine weather and especially to the high temperature 
of the water. 
During my stay at Arcachon the water in the ‘‘bassin” 
