304
_
'.
THE SEAS
mussel bed, such as the one shown in Plate 109, consists, not
of scattered animals, but of a solid massbf mussels of all
'
sizes often six inches deep.
The shell is not itself attached,
but the animal discharges a series of ne, viscid threads
‘
known as ‘.‘ byssus,” which are directed by way of a groove
'
on the thin, extensible “ foot ”
on to a convenient surface
against which they adhere.
They quickly harden in sea
water and form an extremely strong attachment so. that
it takes the most violent storm to break up mussel beds
,
althoughthese are often found on mud ats or stretches of
sand._ So rich are these beds that it is seldom necessary
to cultivate mussels, although it has been found by ex—
periments on the Lancashire coast that small, Stunted
mussels from overcrowded areas speedily grow to large
marketable size when transplanted to new areas.
Many
mussel beds are exposed at low. water and the mussels
«
collected by hand, but others are always under water
so that they have to be shed from boats by means of_
_
dredges.
'
’
,
__
Mussels are, hoWever, culti‘vated on the west coast
of France in the shallow, muddy
called Anse de
_
L’Aiguillon.
The” system of cultivation employed dates
back some Seven hundred years to the
chance
which
'
'
wrecked an Irishnian called Walton, travelling on a small
vessel containing sheep, in this region in 123 5.
He and
some of the sheep—from which it is said certain valuable,
modern
ocks
are
the
descendants—were
the
Only
survivors_ and, in order to obtain a living, he tried to snare
..
sea birds by
of rough grass nets fastened to stakes
'
_
on the muddy shores.
It is doubtful whether he caught
the birds, but quite incidentally he discovered a more
reliable food supply, for young mussels speedily covered
his nets and, becauSe they were raised above the mud in
,
,'
which they would otherwise have been smothered, they
.