Eagle River review. [volume] (Eagle River, Wis.) 1890-1927, 1915-10-01
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the slime pores and canals are greatly developed
and must exude large quantities of slime? Then
too, on deep-sea expeditions, on favorable occa-
sions, for instance, dark calm night fishes
that have been brought to the surface and placed
in water were seen to flash light from the ends
of the tentacles or the phosphorescent pores.
precisely as we should have expected from
study of these organs. Major Alcock, IN MS
interesting volume, "A Naturalist In Indian
Seas mentions a specimen brought up from a
profound depth which "glimmered like ghost
as it lay dead at the bottom Of the pail of tur-
bid seawater" So that by inference, well as
by actual observation, we must believe that what
we call luminous organs in deep-sea hShes emit
light into the darkness about them. In the case
of fishes totally blind, the absence of light is
compensated for by the development OF enor-
nous antennaelike feelers, modified from fin
rays, so that these fishes can feel their way.
as it were, through the darkness.
The absence of light however, entails another
important consequence. AS is well known, 30
plant life can exist in darkness. There is there
fore vegetation of any kind in the profound
depths of the sea- The deep-sea fishes are, in
consequence, all carnvorous the more powerful
ones selling and devouring the weaker ones. 1t
is a cold black world where might reigns SUI
preme. Many have enormous mouths, and for
midable teeth to insure holding the prey. In
some forms the teeth are so large that the mouth
cannot be shut!
depths of the sea, is always low and near the
freezing point. This is true everywhere, even
at the equator Undoubtedly this has an effect
upon the fishes, although it is not yet known
what it is. The amount of oxygen dissolved in
the water also, is much less than in water nearer
the surface. The breathing apparatus of the
deepsea fishes is modified to suit their peculiar
conditions. The gill f1aments have become much
reduced in size and in number of instances
some Of the gill arches bear no gill flaments at
all. The fishes apparently adapted to
much smaller oxygen supply than those living
in rivers or in the shallow sea.
When we think of the vast diversity among
these fishes, the question arises: Are they all
representatives of single family or group that
has become specially adapted to life in the deep
sea: or do they belong to different families or
groups? One need hardly be chthyologist
to answer this question Even cursory exam
ination of the plates in work on deepsea
fishes will show that different types are repre-
sented In fact, great many families are in
Guided in the deep-sea fauna There are sharks
and rays; salmonoids behring's. perches. eels
and representatives of many other families. We
can explain this heterogeneity among them in
this way. We may imagine that fishes of many
different kinds in their search, SO to speak, for
the unoccupied corners of the sea, found haven
in these deeper waters where they were free
from pursuit by their enemies. In the course of
time they migrated farther and farther into the
deep change in habits taking place pari passu
with the changes in structure. Having started
out with different organizations, and possessing
different degrees>of variability, they became diff
ferentiated in diverse directions. that while
some developed enormous mouths powerful
teeth, phosphorescent organs, others became
bottom-living and partly completely lost their
eyes. Still others developed long feelers for
cropping their way through the darkness. Now
and again, however, fishes of separate groups
developed similar structures, so that there are
many striking cases among deep-sea fishes Of
what the biologist calls "convergence" or paral-
lelism.
The museum has recently prepared for exhi-
bition number of typical deep-sea fishes ar
ranged in the form of group. The preparation
of this exhibit involved many technical difficult
ties such as the modelling of the fishes in trans
parent or translucent media to represent them
as glimmering or shining with lit-up portfolios. :
Considerable experimenting was necessary to