.
THE SHELLFISH INDUSTRY.
309.
with the even production of the shell. Mussels and other
,
bivalves show similar
“
disturbance ” rings but not always »
Winter rings.
Oysters increase their shells by sudden
bursts of activity, depositing a broad but very thin layer -
of new shell round the edge at a single operatiOn.
_
This
thin layer is called a “ shoot ” and quickly thickens and
hardens.
The number of “ shoots ”
per annum'varies,
but in this country appears “to be betWeen-two
each-of which in an oySter
two.to three inches…in depth
may mean an increase of about one—third of
.
an
inch all
round the edge.
The_vä.riable number of these
“
shoots .”
makes it quite impossible to- judge the age of an oySter
unless the local conditions are very Well known.
.
_
Hitherto all the molluscs We have considered have been
bivalves, but there are also a number of univalve molluscs,
marine members of the snail family, which are used as
.
food.
Of these perhaps the.periwinkles (Littorina) are the
most important. They-are cOmmon on rocks and stones
between tide-marks from _which they are easily gathered
at low tide.
They are usually boiled before they are eaten.
The commen whelk ,(Buccz‘numundatum)
'
is
larger
than the periwinkle though in other ways very similar.
'
It is not very common on the shore but is taken by drèdging
,
and to some extent in pots.
It
a
strong white or
,
yellowish shell, good sized specimens being some four
‘
inches long by two and a quarter inches. broad.
.
animal within is correspondingly large,“ but the ïesh
.
is
close and tough.
Nevertheless, after boiling —or_ pickling,
they are eaten in tfemer‘1dous numbers. The common
limpet
is also collected and sold as f00d
in many; parts,: but is.extremely tough..
-
' _
»
.
Molluscan shellsh provide a. valùable source of:food.
'
0wing to . the fact that they store great? quantities-Ïof
gly00gen 01— _.“ animalstarch
’.’ as well
asfat
THE SHELLFISH INDUSTRY.
309.
with the even production of the shell. Mussels and other
,
bivalves show similar
“
disturbance ” rings but not always »
Winter rings.
Oysters increase their shells by sudden
bursts of activity, depositing a broad but very thin layer -
of new shell round the edge at a single operatiOn.
_
This
thin layer is called a “ shoot ” and quickly thickens and
hardens.
The number of “ shoots ”
per annum'varies,
but in this country appears “to be betWeen-two
each-of which in an oySter
two.to three inches…in depth
may mean an increase of about one—third of
.
an
inch all
round the edge.
The_vä.riable number of these
“
shoots .”
makes it quite impossible to- judge the age of an oySter
unless the local conditions are very Well known.
.
_
Hitherto all the molluscs We have considered have been
bivalves, but there are also a number of univalve molluscs,
marine members of the snail family, which are used as
.
food.
Of these perhaps the.periwinkles (Littorina) are the
most important. They-are cOmmon on rocks and stones
between tide-marks from _which they are easily gathered
at low tide.
They are usually boiled before they are eaten.
The commen whelk ,(Buccz‘numundatum)
'
is
larger
than the periwinkle though in other ways very similar.
'
It is not very common on the shore but is taken by drèdging
,
and to some extent in pots.
It
a
strong white or
,
yellowish shell, good sized specimens being some four
‘
inches long by two and a quarter inches. broad.
.
animal within is correspondingly large,“ but the ïesh
.
is
close and tough.
Nevertheless, after boiling —or_ pickling,
they are eaten in tfemer‘1dous numbers. The common
limpet
is also collected and sold as f00d
in many; parts,: but is.extremely tough..
-
' _
»
.
Molluscan shellsh provide a. valùable source of:food.
'
0wing to . the fact that they store great? quantities-Ïof
gly00gen 01— _.“ animalstarch
’.’ as well
asfat