…
THE SEAS
-
dication of this tact; nally, however,“ it crumbles away
(Plate 53).
Shipworms do not live long, a year or'perhaps
two years. 'When.-they reach a certain age or‘when there
is no further wood to bore into, they continue the shelly
:
casing over the front îend of the burrow and remain
quiescent within-this, taking such food asthey can obtain
_
from the water,:untilthey die._
:
.
:
'
'
-
The action of the Shipworm in our own waters is much
slower than that of thetropical species.
Here, a piece of
untreated wood is seldom attacked until it has been in
the water for at least a year, whereas in the South Seas
wood will become infected in a few weeks and after… six
weeks show a similar degree of infection to wood which
hasbeen exposed here for eighteen months.
…
There are many different-species of Shipworms but they
all belong to two genera, one called Teredo and the other
Bankia.
All the-British Shipworms belong to the genus
Teredo, of. which three species are found in our seas, and
'
none of
tubes longer than about eighteen
inches, the majority much
.
less, but there are tropical»
Shipworms which are much larger, one, the “
giant Teredo,”
'
being reported to attàin a length of two yards and become
thick as a man’s arm!
The members of the genus
_
"Bahkia —areinhabitantsof the tropics and are easily dis—
_
=
tinguished from Teredo by the structure of the pallets, '
_
which are;paddle—shaped in Teredo but are long and featherlike in
-
.
'
'
'
'
There are two. other bivalve mOlluScs which live in wood._
.
-
One, known as Xylophaga, is commonly found in oating
_.
timbèr in,temperate seas, ithas a shell very like that of
Teredo-‘and it bores in the same manner, but there is no
'
elongate body,the siphons project from the bind end of_the
shell which::completely encloses the body. (Plate 52). The
burrows_aäreîshort, seldom more than oneisa‘nd a half inches .
THE SEAS
-
dication of this tact; nally, however,“ it crumbles away
(Plate 53).
Shipworms do not live long, a year or'perhaps
two years. 'When.-they reach a certain age or‘when there
is no further wood to bore into, they continue the shelly
:
casing over the front îend of the burrow and remain
quiescent within-this, taking such food asthey can obtain
_
from the water,:untilthey die._
:
.
:
'
'
-
The action of the Shipworm in our own waters is much
slower than that of thetropical species.
Here, a piece of
untreated wood is seldom attacked until it has been in
the water for at least a year, whereas in the South Seas
wood will become infected in a few weeks and after… six
weeks show a similar degree of infection to wood which
hasbeen exposed here for eighteen months.
…
There are many different-species of Shipworms but they
all belong to two genera, one called Teredo and the other
Bankia.
All the-British Shipworms belong to the genus
Teredo, of. which three species are found in our seas, and
'
none of
tubes longer than about eighteen
inches, the majority much
.
less, but there are tropical»
Shipworms which are much larger, one, the “
giant Teredo,”
'
being reported to attàin a length of two yards and become
thick as a man’s arm!
The members of the genus
_
"Bahkia —areinhabitantsof the tropics and are easily dis—
_
=
tinguished from Teredo by the structure of the pallets, '
_
which are;paddle—shaped in Teredo but are long and featherlike in
-
.
'
'
'
'
There are two. other bivalve mOlluScs which live in wood._
.
-
One, known as Xylophaga, is commonly found in oating
_.
timbèr in,temperate seas, ithas a shell very like that of
Teredo-‘and it bores in the same manner, but there is no
'
elongate body,the siphons project from the bind end of_the
shell which::completely encloses the body. (Plate 52). The
burrows_aäreîshort, seldom more than oneisa‘nd a half inches .