6 (Den Norske Nordhavs-expedition 1876-1878 / The Norwegian North-Atlantic Expedition 1876-1878 / 4. Bind)

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stærke Muskelbundter, som sammenbindes ved Bindevæv
til en sammenhængende Membran, hvilket ogsaa er
Tilfældet med Længdemusklerne, hvis Bundter dog staa
længere fra hverandre, hvorved Huden paa enkelte Steder af
Kroppen faar ved gjennemfaldende Lys et gittret Udseende,
Fig. 12, h.

Der, hvor det forreste Skjold danner en Fremstaaenhed
paa den udvendige Flade af Kroppen, er en tilsvarende
Fordybning paa deu indvendige Flade, Fig. 6, a, og om
hvilken, (egentlig om Skjoldranden), Ringmusklerne danne
en temmelig tyk Vold, hvorved Hulheden bliver dybere,
-og paa denne Vold fæste den Del af Længdemusklerne sig,
hvilke løbe langs Rygfladen; thi de gaa, ligesaa lidt som
Ringmusklerne, over Skjoldhulen. Derimod er denne
forsynet med et eget Muskelapparat, der bestaar af 20
isolerede Muskler, Fig. 6, b, 14, a, som have en sølvglindsende
Farve, og tage deres Udspring lidt udenfor den føromtalte
Vold, gaar dækket af denne ned i Skjoldhulheden, hvor de
fæste sig dels paa Midten, dels paa den forreste Trediedel
af den indre hule Skjoldvæg. De midterste ere de længste og
have lige Retning, Fig. 14, 5; men alt eftersom de tage
Udspring fra Siderne og fortil, Fig. 14, a, c, blive de kortere
og faa da en skraa Retning, saa at det Hele antager Formen
af en Glorie, Fig. 14. Disse Muskler synes at være
bestemte til at dirigere Skjoldet. Den midterste og forreste
Del af Skjoldhulen er kun beklædt af Peritoneum, der
forresten giver hele Muskelhudens indre Flade sit Overtræk.

Imod den bagerste Kropsende, ved den tidligere
omtalte Fure, blive Ringmusklerne noget tykkere og bidrage
derved til at danne .den før beskrevne Afdeling, Fig 5, c,
paa Kroppens Overflade.

Saavel Ring- som Længdemusklerne ende ved det
bagerste Skjolds Rand, hvis indvendige Flade er næsten plan.

Der er kun en Retractor, der tager sit Udspring paa
Endeskjoldets indre Flade, nærmere Bugsiden, med to
Rødder, Fig. 6, c, og følger saa denne lige op til Spiserøret,
Fig. 6, d, som den forstørstedelen omgiver som en Skede,
indtil den fæster sig strax bagenfor Tentakelkrandsen,
Fig. 6, e.

Spiserøret. Fig. 6,/, der er cylindrisk, smalt og tildels
indesluttet af Retractor, gaar ved en lille Indsnøring over
i den lidt bredere Tarm, som spiralformig gaar bag til
Krops-hulhedens Ende, Fig. 6, g, bøier sig fortil fremdeles i
Spiraler, indtil den gaar over i en temmelig kort Rectum, Fig.
6, h, der aabner sig paa Rygsiden, strax bagenfor det
forreste Skjold.

Tarmspiralen er fæstet til det bagerste Skjolds indre
Flade ved enkelte Bindevævstraade, og Rectum er paa
sin forreste Ende bundet til Huden ved mange flne
muskuløse Traade.

muscles. The former, fig. 12, b, are built up of powerful
muscular fascicles, webbed together as a continuous
membrane by connective tissue; this is likewise the case with
the longitudinal muscles, the fascicles of which are, however,
. less closely arranged, giving to the skin, when held up to
the light, in certain parts of the body a tessellated
appearance, fig. 12, h.

On the outer surface of the body, occurs a
prominence, formed by the shield; and on the inner surface, is
seen a corresponding depression,- fig. 6, a, round whjch (or
rather, round the rim of the shield) the annular muscles
constitute a thickish ridge, increasing the depth of the
excavation : to this ridge are attached such of the longitudinal
muscles as extend • along the dorsal. surface; for neither
the longitudinal nor the annular muscles cross the hollow of
the shield. The shield is provided with a special muscular
apparatus, viz. 20 isolated muscles, figs. 6, b; 14, a, of a
silvery lustre, originating a little without the aforesaid ridge,
under cover of which they pass down into the hollow of
the shield, and are there attached, either to the middle
or to the anterior third of the hollow inner wall. The
medial muscles are the longest, and protend in a right line,
fig. 14, b; but the nearer the point of origin approaches the
sides or the front part, fig. 14, a, c, the shorter and more
oblique do the muscles become, causing the whole assemblage
to resemble a halo, fig. 14. These muscles would seem to
govern the shield. The middle and front part of the
hollow is covered by the peritoneum alone, which also
invests the inner surface of the whole muscular integument.

Near the posterior extremity of the body, along the
groove noticed above, the annular muscles slightly increase
in thickness, and thus contribute towards forming the
section of the surface of the body, fig. 5, c, previously
described.

Both the annular and the longitudinal muscles terminate
at the rim of the posterior shield, the inner surface of which
is almost flat.

This animal has but one retractor, which, springing
from two roots, fig. 6, c, takes its origin oft the inner
surface of the terminal shield, nearest the ventral side,
protending along the latter till it reaches the oesophagus, fig.
6, d, which it almost surrounds, in the form of a sheath,
being affixed immediately posterior to the cincture of
tentacles, fig. 6, e.

The oesophagus, fig 6, /, cylindric, slender, and partially
enclosed by the retractor, passes, with a slight instriction,
into the somewhat wider intestine, which coils spirally back
’to the termination of the perivisceral cavity, fig. 6, g, from
whence, making a bend forwards, it continues on, twisting
spirally as before, till it enters a comparatively short rectum,
fig. 6, h, which opens on the dorsal surface, immediately
posterior to the foremost shield.

The spiral of the intestine is attached to the inner
surface of the hindmost shield by a few filaments of
connective .tissue, and the rectum webbed to the skin at its
anterior extremity by numbers of delicate muscular filaments.

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