'
184
'
THE SEAS
'
aneinones, many worms, starsh, or sea squirts, appears
'
to haveÏno value to the-owner frorh the point of view of
protection‘at any rate.
.
_
'
There are quite denite‘dierences between the colours
of animalsinhabiting different depths in the ocean as is
shoWn clearly in Plate
This has long been known to
sailors and shermen ;
they know that the sh from the
_
surface of the sea in tropical regions are usually sky—blue,
whereas
the
deep—sea sh are always darkly colour'ed,
black, brown, violet or red.
the Cruise of the
Michael Sowà, hauls made in the Sargasso Sea revealed
the presence
“of
ying sh, others of
_
a silvery colour and
young stages of such
sh as the eel ;' at depths of 300 metres sh with silvery
sides and brownish backs were captured, while below 500
metres only black shes and red prawns Were found (Plate
71).
-
-
,
It is noteworthy that these black shes and red prawns
«
only live
the regions where no or very little light can
penetrate, living nearer to the surface in the NorWegia seas
than in the tropics owin'g to the slighter extent t_o whiCh
light penetrates in the former. Another point of interest
is that different species 'o'fthe same genùs,or even different
varieties of the same species, which live: at different depths
are
dierently colour€d, those from the '
greatest“ depths
having the greatest and darkest
The shes
'
from the abyssal région where there is no trace of light '
-
Whatever appear to be usually
blue
violet,
'
part pigmentation can play in the lives—of
'
'
animals ”al‘—ways
by impene'trable darkness _it
.
'
is i=mposSible'ito Say.
:
'
‘
-'
.'
*
'
‘
_Ï ..
'
The connection
light intensity and colour in
marine
difcult to
in some cases the.
f
colour prodü"cë‘d may be protective but this is only the