DRIFTING LIFE
121
below the surface, and then tow_
it slowly along for 'a few
minutes.
The catch will be sufcient reward for the trouble
and the sight of_ the delicate creatures will open one’s eyes
to the amazing abundance and diversity
of this drifting
life that peoplesthe sea in every region of the globe.
The few animals that have so far been mentioned constitute part of what is known as the “
permanent plankton,’f
that is, they live as drifting organisms for the whole
of their
.
lives.
_There “are yet other members of the plankton which
have adopted this mode of life for only a short period in
their lite—history.
In the coastal regions nearly every
_____,—.,…_ -
"
'
"
'
'
,:
._
.
-
…
—' ‘":
'
'
:.'=
y'
=
.
'
: .
_Ü
,
;
\ /”/_
*
},
’
,.
_
".
\
J
_
'
Frs. 26.—Phronima in dead Pyrosôrüa (x 3).
'
animal we nd— has at some time drifted freely andàim—'
lessly about in the water layers above the -botton._' _The
young
the smaller marine animals are, when rst
they batch
from “the egg, extremely small,-_
con—
sequence have insufcientswimming power.to_ cover large
distances, and are unable to copewiththe tides and
rents.
At
this stage, they rise up from the bottom, if hatehed
there, and become members of the plankton
Here they Will
remain for shorter or longer periods, gro'v'Ving ad develOping
until such time as they have assumed their adult characters