OYSTER AND MUSSEL REPORT. 57 
Great numbers of the oysters bred and reared through 
their early stages at Arcachon are sent to Marennes and 
La Tremblade, when from one to two years old, to be 
fattened in a ‘‘ pare d’élevage’”’ and ‘‘ greened”’ by feeding 
upon the diatom Navicula fusiformis, var. ostrearia. 
(See further on in this report under Marennes, p. 58; 
and also under General Conclusions, p. 75). 
Royan. 
This place is situated at the mouth of the Gironde, and 
is a centre of the sardine fishing. I found there a fleet of 
between 60 and 70 fishing boats carrying a trawl with a 
beam of about 20 feet. Shrimping also is carried on by 
means of fixed or suspended nets worked both from the 
long breakwater and also from the boats. The net is 
shaped as a shallow bag and is about 6 feet in diameter. 
It has either a hoop round the mouth or is attached to 
four light spars set in the form of a square. This frame- 
work is then suspended by a rope which passes over a 
pulley at the end of a long pole, on the breakwater, or a 
light boom, on the boat, set at such an angle that the net 
can be conveniently lowered into the water. Some bait 
is put in the centre of the net and after it has been down 
a short time it is hauled up rapidly and the shrimps are 
thus caught in the concavity of the net. 
On the rocks to the north of Royan I found many small 
natural oysters which the people go out at low tide to 
collect, and to eat largely on the spot. The rocks here 
are a richly fossiliferous limestone (cretaceous), and the 
oysters seem to have rather thick, irregular, sometimes 
distorted shells. Most of them adhere completely by one 
valve, and are attached to the rocks in fair abundance 
from low water mark up to at least half tide. They seem 
to be mostly 2 or 3 years old, and are not really good to eat, 
