COLOUR AND PHOSPHORESCENCE
191
passes a nerve which controls it———for the luminescence of
these animals is under
and the light organs
_
'
can be turned off and on at will like an electric torch.
The
organs are also well supplied with blood for, since they are
shut off completely from the water,_they are unable to get
the oxygen, which, as we have seen, is necessary for the
production oflight, except from the blood stream.
typical light organ of this kind is shown in section in Figure
40—
în the chapter on boring life we discussed the bivalve
, ‘\
[
//——_\\
-
P
////,
\
\
;
::_/Çç/ÿ/\\\\
.
_
/
—/'/'/
\
/.
\“
'
_
-
-
Γs—
=
-
r.
p.
,
,
,
F1G. 4o.—Light-producing organ of a crustacean, Sergestes. l., len's of
'
.
'
several layers; p., layer of dark pigment behind reeÇtor; pb., '
photogenic cells where light is produced; r., reector. (Modied after
Terao.)
_
mollusc known as the Piddock (Pholas) (Fig. 41) which
‘
bores its way into rock where it lives with Onlythe tips
of its siphons projecting into' the water;
This Creature,
,
strangely enough, is one of the mOst 1uininescent of marine
animals, a fact which has been known from very early
times… There are no special ofgans but light is produced
within minute glands present in ve areas on the skin
and spreads from these all over the surface of the body.
=
‘The light is a greenish blue and very poWerîul.
Passing
191
passes a nerve which controls it———for the luminescence of
these animals is under
and the light organs
_
'
can be turned off and on at will like an electric torch.
The
organs are also well supplied with blood for, since they are
shut off completely from the water,_they are unable to get
the oxygen, which, as we have seen, is necessary for the
production oflight, except from the blood stream.
typical light organ of this kind is shown in section in Figure
40—
în the chapter on boring life we discussed the bivalve
, ‘\
[
//——_\\
-
P
////,
\
\
;
::_/Çç/ÿ/\\\\
.
_
/
—/'/'/
\
/.
\“
'
_
-
-
Γs—
=
-
r.
p.
,
,
,
F1G. 4o.—Light-producing organ of a crustacean, Sergestes. l., len's of
'
.
'
several layers; p., layer of dark pigment behind reeÇtor; pb., '
photogenic cells where light is produced; r., reector. (Modied after
Terao.)
_
mollusc known as the Piddock (Pholas) (Fig. 41) which
‘
bores its way into rock where it lives with Onlythe tips
of its siphons projecting into' the water;
This Creature,
,
strangely enough, is one of the mOst 1uininescent of marine
animals, a fact which has been known from very early
times… There are no special ofgans but light is produced
within minute glands present in ve areas on the skin
and spreads from these all over the surface of the body.
=
‘The light is a greenish blue and very poWerîul.
Passing