Full resolution (JPEG) - On this page / på denna sida - Sidor ...
<< prev. page << föreg. sida << >> nästa sida >> next page >>
Below is the raw OCR text
from the above scanned image.
Do you see an error? Proofread the page now!
Här nedan syns maskintolkade texten från faksimilbilden ovan.
Ser du något fel? Korrekturläs sidan nu!
This page has never been proofread. / Denna sida har aldrig korrekturlästs.
med et Ord selve Æggestokken, der for ham var ukjendt.
Det er neppe nogen Tvivl underkastet, -at de
Organer Max Müller kalder Æggestokke ere fuldstændig
homologe med de af os beskrevne Æggebeholdere hos Hamingia,
ihvorvel de i Formen afvige noget; men lægger man Mærke
til, at Müller omtaler en lille Fremstaaenhed. paa hvilken
han tror at have fundet en Aabning. kan dette neppe være
noget andet, eud den hos Hamingia og Bonéllia paa Uterus
værende Tragt, der tjener til at opsamle og lede de i
Kropshulheden frit svømmende Æg ind i Æggebeholderen.
Hos Thalassema foregaar, efter Semper’s og Spengel’s
Iagttagelser, Ægdannelsen paa en aldeles lignende Maade,
som hos Bonéllia.
Vi mene saaledes at have bevist, at den af os
opstillede nye Slægt staar i et nært Forhold til Thalassema og
Bonéllia; men ser man hen til, at der hos vor Slægt, baade
i de ydre Karakterer og i Anatomien er størst Fællesskab
med Bonéllia, turde det være et Spørgsmaal om den ikke
i phylogenetisk Henseende staar i den inderligste Rapport
til denne. Hamingia bærer virkelig Spor af en fordums
Snabel, der tør være forsvunden, og ved hvis Forsvinden
naturligvis saavel Circulations- som Nervesystemet maatte
undergaa nogen Forandring, hvilket jo viser sig at være
Tilfældet, idet den kredsformige Dannelse af de nævnte
Systemer, hvilken foregaar i Snabelen hos Bonéllia, træder
op hos Hamingia under Fonn af en Nervex-ing og
Blodkarring, der omgive den forreste Del af Spiserøret.
Kan det antages, at Bonellien oprindelig har havt to
Uteri, hvilket kan være rimeligt nok, da den ene har et
meget usymetrisk Leie, og kommer dertil, at
Lacaze-Duthiers har fundet hos et Exemplar 2 Uteri, som han
forresten angiver som ganske exceptionelt, — saa er det ikke
noget ukjendt, at det tabte Orgau atter optræder i en høiere
Afstamning, og vi ere tilbøielige til at antage, at Hamingia
staar noget høiere i Organisationsrækken end Bonéllia.
Hamingia ardica lever paa sandholdig Lerbund,
bevæger sig temmelig meget ved Krumninger i forskjellige
Retninger, uden at gjøre nogen synderlig Fremgang.
Farven er mørk græsgrøn, naar Dyret er
sammentrukket, men bliver lysere med enkelte møx’kere Partier,
naar det er udspændt, og da bliver Huden saa
gjennem-sigtig, at en Del af Tarmkanalen kan sees. Mundskiven
med Mundlæberue ere næsten hvide, spillende lidt i det
Gule, ligeledes de lange cylindriske, krumbøiede Papiller
paa Bugfladen.
Kun et Exemplar blev fundet paa Station 290.
Slægtskarakter.
Legemet valsefornxigt. Mundexx paa den forreste Ende.
nærmere Bugfladen. Analaabningen i Centrum af den
Den norske Nordhavsexpedition. Panielssen og Koren: Gepliyrea.
ingly uteri, though he does not even allude to the true
ovary, of whose existence indeed he knew nothing.
Meanwhile, it will hardly admit of doubt, that the
organs by Max Miiller termed ovaries are strictly
homologous with the uteri, or uterine pouches, in
Hamingia, though slightly different as to form; but calling to
mind the minute papilla mentioned by Miiller. and in
which he believes to have detected an opening, the latter
must assuredly be the funnel-shaped aperture which in
Hamingia and Bonéllia serves for the reception of the ova
floating in the perivisceral cavity, and to afford them egress
on their passage into the uterine pouch.
In Thalassema, according to Semper’s and Spengel’s
observations, the ova are developed precisely as in Bonellia.
Hence we conceive to have shown, that the genus
established in this Memoir is closely allied alike to
Thalassema and to Bonellia; but whereas Hamingia, both as
regards its habitus and anatomical structure, exhibits
greatest resemblance to Bonellia, it is a question whether,
phyl-ogenetically too. the new genus will not prove to have most
intimate relations with that animal. For Hamingia does
indeed retain traces of a proboscis, once distinguishing the
genus Bonellia, and the loss of which must naturally to
some extent have modified the characteristics of the
circulatory and nervous systems. And this is foxxnd to be the
case; for the semi-circular formation of the said systems
in the proboscis of Bonellia, occurs in Hamingia as a
nervous ring and an annulary vascular blood-vessel, which
represent together the anterior portion of the oesophagus.
Now, assuming Bonellia to have had originally two
uterine pouches, — for the single uterus with which it is
now furnished is anything but symmetrical in position, —
and calling to mind, too, that Lacaze-Duthiers records his
having once found two uteri in a specimen of this genus
(quite an exceptional case, however, in his opinion) —
science is not without instances in point showing the organ
thus lost to have developed again in a congener of higher
extraction; and we are indeed disposed to regard Hamingia
as ranking above Bonellia in the scale of organisation.
Hamingia ardica affects a bottom of sabulous clay,
moves about a good deal in disrupted curves, without
however making much progress.
Colour, when the animal is contracted, a dark
grassy-green, but lighter, with a few darkish patches, when it
blows itself out; the skin is then so translucent, that part
of the intestinal canal may be seen through it. Buccal
disk and lips almost white, with a faint tinge of yellow;
likewise the long, cylindrical, arcuate papillæ of the
ventral surface.
One example only, at Station 290.
Generic Character.
Body cylindrical; mouth at the anterior extremity,
nearest the ventral surface. Anal opening in the centre
<< prev. page << föreg. sida << >> nästa sida >> next page >>
