154
»THE BIOLOGY OF ‘FISHES
_
.
Only in a few shes supposed to live on the bottom'_
do ordinary glandular, luminous organs occur
and only as isolated organs,
not in such numbers as in thef
genuine luminous -shes. The oceanic Scopelids are the
,
'
forms which have the most and best developed organe, and {gi
among these the surface forms of the genus Myctophur’n
Ï
,
possess
the largest, whilst Lampayctus (from 600 and
i
800 metres) has very small organs. The deepest forms of ;
;
shes (Aceratias, Melamphaes, Cetomimus) have no luminOus
organs,_ and it appears that these are specially characteristic .' Âf—=L ,
of the shes which live in the upper 500 metres in warm
oceanic waters.
_
..
__
Î
,
‘
—
The last point seems of great importance in the consider—' ' —Ï_,}Ï{ ,
of the occurrence and usefulness of these organs.’ A
.
blacksh, Paraliparis bathybii, that lives in the depths
‘ïï
of the NorWegian Sea, posseSseswell-developed eyes but no
_
,
luminous Organs'.
The temperature has thus something to.
};î ,
do with the phenomenon. The water in oceaic depths‘ is
‘
much colder
in the upper layers, down to 500 metres—', '
and it may be recalled that the red rays of light "penetratë
only downto about 100 metres, whilst the ultra—violet and,
î
_
râÿs: can. bedetected still at1‘000 =metres. ’ We may
_
therefore in general,that bot—h light and warmth arenecés‘saräÿ
[’
_
for the production of luminant energy, and it may be that Ï
:
the'luminescence of the skin inabyssal_-formsWhenbr0ught
’
_
,
»to the surface is due tothe latter fact, We canot;be certain
:
_,îhê-‘C the shwe'relùminæcet
;,
'
Thelummesceut
the body, _
nbb1nntd…ththlw…m
on the“
:; , t0P0ftheheadFrequentlytheyare àrrai1ged i fôWsfaloñä— Îfi
:
”
thebOdÿ or1ntransversc bâtis bbtween
j
,
,
’
'
i,}Ëffiâlr
,
over the ;
—
,
,
l body;äbut they dôirî1b't::tiàppéaf5iéaièaäè1umlnous ring-sami;
'1
‘fhç.ffœnsre
î
sunkdeepbmtheskm mth thesecretmnformmgdense
—
'
Of
t‘Cübù1€s ÏrayÏ—be‘rtsti-11Αîçlèëpët2 With '
»THE BIOLOGY OF ‘FISHES
_
.
Only in a few shes supposed to live on the bottom'_
do ordinary glandular, luminous organs occur
and only as isolated organs,
not in such numbers as in thef
genuine luminous -shes. The oceanic Scopelids are the
,
'
forms which have the most and best developed organe, and {gi
among these the surface forms of the genus Myctophur’n
Ï
,
possess
the largest, whilst Lampayctus (from 600 and
i
800 metres) has very small organs. The deepest forms of ;
;
shes (Aceratias, Melamphaes, Cetomimus) have no luminOus
organs,_ and it appears that these are specially characteristic .' Âf—=L ,
of the shes which live in the upper 500 metres in warm
oceanic waters.
_
..
__
Î
,
‘
—
The last point seems of great importance in the consider—' ' —Ï_,}Ï{ ,
of the occurrence and usefulness of these organs.’ A
.
blacksh, Paraliparis bathybii, that lives in the depths
‘ïï
of the NorWegian Sea, posseSseswell-developed eyes but no
_
,
luminous Organs'.
The temperature has thus something to.
};î ,
do with the phenomenon. The water in oceaic depths‘ is
‘
much colder
in the upper layers, down to 500 metres—', '
and it may be recalled that the red rays of light "penetratë
only downto about 100 metres, whilst the ultra—violet and,
î
_
râÿs: can. bedetected still at1‘000 =metres. ’ We may
_
therefore in general,that bot—h light and warmth arenecés‘saräÿ
[’
_
for the production of luminant energy, and it may be that Ï
:
the'luminescence of the skin inabyssal_-formsWhenbr0ught
’
_
,
»to the surface is due tothe latter fact, We canot;be certain
:
_,îhê-‘C the shwe'relùminæcet
;,
'
Thelummesceut
the body, _
nbb1nntd…ththlw…m
on the“
:; , t0P0ftheheadFrequentlytheyare àrrai1ged i fôWsfaloñä— Îfi
:
”
thebOdÿ or1ntransversc bâtis bbtween
j
,
,
’
'
i,}Ëffiâlr
,
over the ;
—
,
,
l body;äbut they dôirî1b't::tiàppéaf5iéaièaäè1umlnous ring-sami;
'1
‘fhç.ffœnsre
î
sunkdeepbmtheskm mth thesecretmnformmgdense
—
'
Of
t‘Cübù1€s ÏrayÏ—be‘rtsti-11Αîçlèëpët2 With '