400 SUPPLEMENT 
stagnant, and where a greater or less quantity of fresh-water 
can be introduced. These bouchots are formed with two 
ranks of stakes, intertwisted with poles, and united so as to 
form an angle, the summit of which is opposite to the sea. 
They are placed on a muddy bottom of great depth at the 
mouth of the Seine, and to the west of Aunis. The mussels 
which are there attached, deposit their spawn, which is shel- 
tered in the branches ofa sort of coralline which abounds 
very much on the wood of the bouchots. At the end of some 
months, part of the mussels are detached from among those 
which are too much accumulated, and they are distributed in 
such places as were unfurnished with them. To facilitate 
their adherence, they are carefully engaged in the hurdle- 
work, and even, for greater precaution, they are enveloped 
with a net, without which they would be soon carried off by 
the waves. The mussels multiply in these bouchots in the 
proportion of ten to one in the same year. They are gathered 
from the end of July, for more than six months, either at low 
water, or by the assistance of a machine named acon*. The 
product of these bouchots would be considerable, were it not 
for the expense of repairing the wood, which has been gnawed 
by the teredo since 1720, at which time this species of mol- 
lusca was introduced by a vessel wrecked upon the coast. 
Besides the human species, mussels have a great number of 
other enemies ; many sea-birds detach them from their situa- 
tion, by breaking the shell, and then feeding on them. Many 
cephalous mollusca, and among others the turbo littoralis, 
according to the observation of Reaumur, pierce the shell 
with their proboscis, and suck the soft parts. 
The fresh-water mussels, (ANODONTES) are, some of them, 
very large, particularly the species called mytilus cygneus. 
The heart of this animal is remarkably large, and the foot 
* Acon, or accon, signifies a sort of flat-bottomed boat. 
