112
.
THE SEAS
_
.
and the word is now in general use among those interested
in the science of the sea.
.
PLANKTON PLANTS
One naturally wishes to know what kinds of creatures
_
these are that make up the almost innite multitudes that
,
drift freely throughout the water layers.
The plankton is
now known to play a part of the greatest importancein the
economy of the sea, and in this respect the organisms that
deserve our rst consideration are the microscopic plants.
These are not like the plants on land, but consist generally
each only-of a single cell ; nevertheless, they are plants in
'
'
the true sense of the word, because each contains within its
cell colouîing matter closely similar to that so characteristic ‘
of our land vegetation.
These little plants are known_as
“
diatoms ”
;
they_are so called because they have, sur'
rounding their cell—walls, glass—like protective shells com—
posed of two ‘halves—two lid-like structures that t-‘ one
.
_
into the other, and thus enclose the body of the plant ina
little box.
-
'
'
_
In order to catch these diatoms it is necessary to use a
'
net made of the nest muslim or Silk, as they
so
sinall that they Will pass through the meshes of ordinary
_
coarse muslin.
The catch, to the naked eye, will look like“
'
a grèenish-brownscum, and if placed under the microscope
will be seen to consist of a jumble of interlacing spines-'
amongst which may be noticed green «oblongs, squares
and
circles.
Io nd out the true nature of the catch it must '
be diluted with sea water and only a drop examined, when'
,
itwillbe iound'that the diatoms are much fewer in number -
and separated one from the other so that their true structures
can be made out.
Some will be like little circular discs,
'
others oblong with little spines or horns pr0j ecting from each
.
'
”corner, and others strung together to form chains of tiny _
.
THE SEAS
_
.
and the word is now in general use among those interested
in the science of the sea.
.
PLANKTON PLANTS
One naturally wishes to know what kinds of creatures
_
these are that make up the almost innite multitudes that
,
drift freely throughout the water layers.
The plankton is
now known to play a part of the greatest importancein the
economy of the sea, and in this respect the organisms that
deserve our rst consideration are the microscopic plants.
These are not like the plants on land, but consist generally
each only-of a single cell ; nevertheless, they are plants in
'
'
the true sense of the word, because each contains within its
cell colouîing matter closely similar to that so characteristic ‘
of our land vegetation.
These little plants are known_as
“
diatoms ”
;
they_are so called because they have, sur'
rounding their cell—walls, glass—like protective shells com—
posed of two ‘halves—two lid-like structures that t-‘ one
.
_
into the other, and thus enclose the body of the plant ina
little box.
-
'
'
_
In order to catch these diatoms it is necessary to use a
'
net made of the nest muslim or Silk, as they
so
sinall that they Will pass through the meshes of ordinary
_
coarse muslin.
The catch, to the naked eye, will look like“
'
a grèenish-brownscum, and if placed under the microscope
will be seen to consist of a jumble of interlacing spines-'
amongst which may be noticed green «oblongs, squares
and
circles.
Io nd out the true nature of the catch it must '
be diluted with sea water and only a drop examined, when'
,
itwillbe iound'that the diatoms are much fewer in number -
and separated one from the other so that their true structures
can be made out.
Some will be like little circular discs,
'
others oblong with little spines or horns pr0j ecting from each
.
'
”corner, and others strung together to form chains of tiny _