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44
viste i alt væsentligt fuldkommen samme Bygning som hos
fuldvoxne Individer, uden at det mindste Spor af nogen
forudgaaende Larvetilstand var at bemærke hos samme.
Forekomst og Levevis. Ifølge sin hele Organisation
synes den her omhandlede Form at maatte antages at føre
et Slags halvt pelagiskt Liv; men andre Ord, jeg har Grund
til at antage, at den ikke som de i det foregaaende omtalte
Former er strengt bunden til selve Havbunden, men streifer
frit om i Vandet. Dog tyder Øinenes rudimentære
Beskaffenhed med Bestemthed hen paa, at dens Ophold
væsentlig kun kan være indskrænket til de dybere Vandlag; noget
der ogsaa vinder fuld Bekræftelse ved de under vor
Expedition gjorte Erfaringer. Alle de af os erholdte
Exemplarer er nemlig optagne ved Hjælp af Bundskraben eller
Trawlnettet fra de største Dybder i den kolde Area, fra
452 til 1862 Favne. Paa grundere Vand liar vi aldrig
faaet den op, heller ikke nogensinde i Overfladenettet,
skjøndt dette i stor Udstrækning har været benyttet under
Expeditionen.
Endelig fortjener det at bemærkes, at R. Collett har
fundet Levninger af nærværende Krebs i Ventrikelen hos
et Par Dybvandsfiske, hvis Organisation er en saadan, at
de med Sikkerhed maa antages ikke at kunne gjøre meget
lange Udflugter fra Havbunden, nemlig Raja hyperiorea
Collett, og Lycodes frigidris Collett, begge optagne fra det
store Dyb i den kolde Area.
Som en Mærkelighed fortjener det dog her at anføres,
at det af Buchholz undersøgte Exemplar blev, som det
heder, taget lige i Vandskorpen. Hvis dette virkelig
forholder sig saa, maa det dog antages at have været et ganske
anomalt Træf. Exemplaret maa vel af en eller anden
tilfældig Aarsag, ved Undervandsstrøm eller paa anden Maade»
være bleven bragt op fra de dybere Vandlag, hvor Arten
aabenbart maa antages at have sit rette Hjem.
Skjøndt denne Krebs ifølge sine kraftigt udviklede
Svommeredskaber og ringe specifiske Vægt maa antages at
være et særdeles livligt Dyr, var der dog altid kun yderst
svage Livsytringer at se lios de af os indfangede Individer,
og det uagtet disse som oftest erholdtes i fuldkommen
ubeskadiget Tilstand og hurtigst muligt efter Indfangningen
blev isolerede i Kar med friskt Søvand. Det synes klart,
at Grunden hertil maa være den, at Dyret ved saaledes
pludseligt at bringes op til Dagens Lys fra de enorme Dyb,
hvori det har sit Tilhold, hensættes under saa abnorme
Forhold, at alle Livsfunctioner herved bliver ligesom
lam-slaaede. Noget lignende observeres forøvrigt ogsaa i mere
eller mindre Grad med de fleste øvrige paa store Dyb
levende Sødyr.
Udbredning. Det af Buchholz beskrevne Individ
erholdtes, som anført, i Havet Øst for Grønland og nær den
74de Bredegrad. Under vor Expedition har vi taget den
nærværende Form paa ikke mindre end 14 forskjellige
Stationer. samtlige tilhørende den kolde Area. Endelig er af
ß. Collett fundet Levninger af et Exemplar i Ventrikelen
af en Lycodes frigidlis fra Ståt. 353, hvorfra vi ikke har
noteret denne Krebs.
length, exhibited in all essential characters precisely the
same structure as full-grown individuals, without its being
possible to detect the slightest trace of a previous larval
stage.
Occurrence and Habits. — Judging from its whole
organization, the form here treated of would appear to lead
a kind of semi-pelagic existence; in other words, I have reason
to suppose, that, unlike the forms previously recorded, this
animal is not strictly confined to the sea-bottom, but cail move
about freely through the water. Meanwhile, the rudimentary
character of the eyes indicate with absolute certainty its
habitat as chiefly lying in the deeper strata, a fact to which
the experience derived on the Norwegian Expedition gives
full confirmation. All of the specimens collected were
brought up in the dredge or trawl from the greatest depths
in the cold area — 452 to 1862 fathoms. In shallower
water we never took it, nor in the surface-net, which
notwithstanding was extensively used on the Expedition.
Finally, I will not fail to remark that Mr. It. Collett
has found the remains of this form in the ventricle of one
or two deep-water fishes whose organization is such as
must infallibly prevent them from ascending to any great
distance from the sea-bed, viz. — Raja liyperborea Collett
and Lycodes frigidus Collett, both brought up from the great
depths of the cold area.
As a remarkable coincidence, it is worthy of note,
that the specimen examined by Buchholz is said to have
been taken at the surface of the water. Assuming this to
have actually been the case, we cannot but regard it as
anomolous. The animal had probably from some incidental
circumstance, by an undercurrent or in some other manner,
been carried up from the deeper strata, where the species
must obviously be assumed to have its true habitat.
Though the form described above, judging from its
powerfully developed natatory organs and trifling specific
weight, must be deemed an exceedingly vivacious animal,
the specimens we succeeded in collecting gave without
exception but very faint manifestations of life, notwithstanding
they were captured as a rule in a perfectly unmutilated
state and as soon as possible isolated in a vessel containing
fresh sea-water. The reason of this must clearly be, that
the animal, on being suddenly brought up to the light of
day from the enormous depths it inhabits, is placed in such
abnormal conditions as cannot fail to paralyze all its vital
functions. For the rest, similar phenomena may be
observed, to a greater or less extent, in most other marine
animals whose habitat is the great depths of the ocean.
Distribution. — The specimen described by Buchholz
was taken, as previously stated, in the open sea, east of
Greenland, and near the 74tli parallel of latitude. On
the Norwegian Expedition, the form occurred at not less
than 14 different Stations, all in the cold area. Finally.
Mr. R. Collett found the remains of a specimen in the
ventricle of Lycodes frigidus, at Ståt. 353, from which
we had not recorded this Crustacean.
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