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125
Fadderne (Fig. 40 og 41) er samtlige ægte
Gang-fodder, uden at nogen af dem en modificeret til
Griberedska-ber. De tiltager jevnt i Længde bagtil, saa at sidste Par
(Fig. 41) omtrent er en halv Gang til saa langt som 1ste
Par (Fig. 40). De er temmelig spinkle og alle af
fuldkommen ens Bygning, kun tyndt børstebesatte og endende
med en simpel, svagt bøiet Klo.
Bagkroppens Operculum (se Fig. 42) er forholdsvis
meget lidet, kun indtagende et meget begrændset Rum af
Segmentets nedre Flade, og viser en uregelmæssig afrundet
Form. I den bagre Kant er det fint cilieret, og langs
Midten løber en stump Kjøl, der dog ikke som hos den
typiske Art danner noget tandformigt Fremspring.
De under Operculet skjulte Buglemmer, 4 Par i Tallet,
er alle ægte Respirationsorganer og af en meget blød og
fragil Consistens, uden nogen tydelig Adskillelse mellem
Stamme og Endeplader.
1ste Par (Fig. 43) har den ydre Plade meget liden
og smal, langs den ydre Kant tæt cilieret og ved Spidsen
forsynet ined en enkelt stærk Børste.
2det Par (Fig. 44) har denne Plade ligeledes meget
liden, men af bredere, hjertedannet Form og i den ydre
Kant forsynet med 3 Fjærborster.
De 2 øvrige Par synes kun at bestaa af enkle,
børste-lose Plader.
Halevedhængene, der rager frem fra Enden af
Bag-kropssegmentet umiddelbart indenfor de tandformige laterale
Fremspring (se Fig. 31, 42 og 45), er meget smaa og, uligt
hvad Tilfældet er hos den typiske Art, ganske simple, kun
bestaaende af et enkelt koniskt, med en Del fine Børster
forsynet Led.
Dyrets Farve er som hos N. oblongus ensformig hvid,
uden nogen Pigmentering.
Længden overstiger neppe 3™™.
Forekomst og Udbredning. Denne lille
characteristiske Isopode er observeret paa 4 forskjellige Stationer,
men paa alle kun ganske enkeltvis, noget, der vel for en
Del maa tilskrives dens ringe Størrelse og uanselige Farve,
hvorved den let unddrager sig Opmærksomheden. Af disse
Stationer, som samtlige, med Undtagelse af en enkelt (Ståt.
290) tilhører den kolde Area, ligger en (Ståt. 33) i Havet
udenfor Romsdalen, en anden (Ståt. 192) i Havet Vest af
Tromsø, en 3die (Ståt. 290) omtrent midtveis mellem
Finmarken og Beeren Eiland, den 4de endelig (Ståt. 51) i
Havet Øst af Island. Dybden paa disse Stationer varierer
fra 191 til 1163 Favne.
Artens for Tiden bekjendte Udbredningsfelt er
saaledes de større Dybder i Nordhavet fra den 63de til den
73de Bredegrad.
The legs (figs. 40, 41) are all true pereiopoda, none
of them modified to serve as organs of prey. They
increase successively in length, the last pair (fig. 41) being
about half as long again as the first (fig. 40). They are
rather slender, all perfectly uniform in structure, but
sparingly furnished with bristles, and terminate in a simple,
faintly curving claw.
The operculum of the abdomen (see fig. 42) is
comparatively very small, occupying but an exceedingly limited
space on the lower face of the segment, and has an
irregular-rounded form. Its posterior margin is finely ciliated;
and, along the middle, runs an obtuse carina, not however,
as in the typical species, constituting any dentiform
projection.
The abdominal limbs — 4 pairs — concealed
beneath the operculum, are all true respiratory organs,
exceedingly soft and fragile, and have no distinct separation
between the trunk and the terminal plates.
Tile 1st pair (fig. 43) have the outer plate very small
and narrow, densely ciliated along the outer edge and
furnished at the point with a single strong bristle.
The 2nd pair (fig. 44) have this plate likewise
exceedingly small, but of a broader, cordiform shape, and
furnished along the outer margin with 3 plumous bristles.
The 2 remaining pairs would appear to consist of
merely simple, naked plates.
Thd caudal appendages, jutting forth from the
extremity of the abdominal segment, immediately within the
dentiform lateral projections (see figs. 31, 42, and 45), are
exceedingly small, and, contrary to what is the case in the
typical species, quite simple in structure, consisting of but
one conical joint, furnished with a number of delicate
bristles.
Colour of the animal, as in iV. oblongus, a uniform
white, without any trace of pigment.
Length scarcely, if at all, exceeding 3’"™.
Occurrence and Distribution. — Tilis minute,
characteristic Isopod was taken at 4 different Stations, but in
each locality isolated, a circumstance that no doubt must
be partly ascribed to its trifling size and well-nigh
inconspicuous colour, which would easily cause it to escape attention.
Of these Stations, that, with the exception of one (Ståt. 290),
all belong to the cold area, the first (Ståt. 33) lies off the
coast of Romsdalen, the second (Ståt. 192) in the open
sea west of Tromsø, the third (Ståt. 290) about midway
between Finmark and Beeren Eiland, and the fourth (Ståt.
51) in the open sea east of Iceland. The depth at these
Stations ranged from 191 to 1163 fathoms.
Hence, the tract throughout which the species is at
present known to be distributed, comprises the great depths
of the Northern Ocean, extending from the 63rd to the
73rd parallel of latitude.
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