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42
or «len mindst fortrukne; men ogsaa den er bleven noget
forrykket, ligesom den er mere langstrakt, end Tilfældet
er længere nede paa Stilken, Fig. 30, d. Den venstre
Sidekanal er loftet op og er trangere, Fig. 30, e, — kort sagt,
alle Længdekanalerne ere trukne mod Dorsalfladen, der
ogsaa er meget udvidet, ligesom Coenencliymet her er
meget tykt, Fig. 30, /’, imedens det paa VentralHaden er
overordentligt tyndt,. Fig. 30, g. De 4 Septa ere fortrukne
i Lighed med Kanalerne. Disse ere meel Hensyn til deres
Lumen ingenlunde formindskede, de ere kun blevne mere
udstrakte i Bredden i den skedeformige Udvidning, — en
Anordning, der bidrager til, at denne Del kan betydeligt
opsvulme og udspændes af den i Kanalerne cirkulerende
Vædske. Det forholder sig ikke saaledes, som Dr. Lindahl
i sin Afhandling "om Pennatulid-Slägtet Umbelhda" angiver,
"at Dorsalkanalen er den hovedsagelig udvidede Kanal, der
giver den skedeformige Udvidning sin Form, og at den ved
en eller anden Anledning, ved indesluttede Gasers
Expansion kan blæres op;" Forholdet er som ovenfor antydet
meget simplere.
Figur 31 illustrerer Længdekanalerne lige ved
Begyndelsen af Hachis. Axen er her endnu mere fordreiet;
Ventralkanalen er ganske fortrukken, Fig. 31,«;
Dorsalkanalen, Fig. 31, b, har næsten sin naturlige Fonn, naar undtages,
at den er udvidet efter Dorsalfiadons Bredde, og
Sidekanalerne, Fig. 31, c, c, ere ligeledes betydeligt udvidede paa
Dorsalsiden. Samtlige Kanaler ere temmelig smale ved
Axen men udvider sig stærkt mod Coeneuchyinvæggeii. Fig.
30. 31. Op igjennem Hachis blive Sidekanalerne noget
smalere, indtil de op imod Terniinalpolypeu ophøre, idet
begge Septa paa. liver Side smelte sammen, saa at der
bliver kun to Kanaler, nemlig Dorsal- og Ventralkanalen,
hvoraf den første bliver trangere og trangere, indtil ogsaa
den forsvinder nogle Millimeter fra Terniinalpolypeu.
Ventralkanalen, der er endnu temmelig vid, og hvori Axen
ender, gjør en stærk Bøining under Endepolypen, smalner
betydeligt af og ender paa Ventralsiden, 4—5""" linder
Tcr-minalböiypens Gruncl, i en rund, gjennomboret Papille.
I den bulbøse Del af Stilken ere de 4 Længdekanaler
kun liden Forandring underkastede, hvorimod de 4 Septa
mærkeligt modificeres, ligesom et Septum transversale
optræder. Omtrent 10""" fra Stokkens Grund deler det
ven-tral-laterale Septum paa liver Side sig i to Længdefolder;
den ene, bagerste, Fig. 32, a gaar hen og insererer sig
langs Sidedelen at’ Axons Skede lige ned til dennes Ende,
om hvilken den slaar sig, og er her sammenvoxen med den
tilsvarende fra den anden Side. Fig. 33, «; den anden,
forreste, Fold, Fig. 32, b. der er den tykkeste, gaar paaskraas
nedad og indad foran Axeskeden og moder paa Midten af
VentralHaden en tilsvarende Fold fra den anden Side, med
towards the lateral canal (Hg. 30, b). The right lateral canal is
drawn towards the dorsal canal, and is pretty much dilated
towards the wall of the sarcosoma (fig. 30, c). The dorsal canal
is the least distorted, but, it is, also, somewhat displaced,
whilst, also, it is more elongated, than is the case further
down the stem (Hg. 30, d). The left lateral canal is
elevated and narrower (Hg. 30, e); in short: all the
longitudinal canals are drawn towards the dorsal surface, which,
also, is much dilated, and the sarcosoma is, also, very
thick here (Hg. 30, /); whilst, on the ventral surface, it is
extremely thin (fig. 30, rj). The 4 septa are distorted,
similar to the canals. These are, so far as regards their
channel, in no way diminished; they have, only, become
dilated in breadth throughout tile sheath-formed dilation,
an arrangement which conduces to the canals becoming
capable, of being considerably swollen and expanded by the
Huids circulating in them. It is not the case, as Dr. Lindahl
in his memoir "om Pennatulid-Slägtet Untbéllida" states
it to be. viz. that the dorsal canal is the* principal dilated
canal which gives to the sheath-formed dilation it’s shape,
and that it may on some one or other occasion, be
expanded by the elastic action of the enclosed gases. The
real case is, as above explained, much simpler.
Fig. 31 illustrates the longitudinal canals as seen,
exactly at the coninieiicement of the rachis. The axis
is, here, still more twisted; and the ventral canal is quite
distorted (fig. 31, a). The dorsal canal (fig. 31. b) has
almost the natural shape, with the exception, that it is
dilated throughout the breadth of the dorsal surface; and the
lateral canals (Hg. 31, c, c) are also considerably dilated
on the dorsal side. All of tin; canals are rather narrow
close to the axis, but become greatly dilated towards the
wall of the sarcosoma (Hg. 30, 31). Upwards, throughout
the rachis, the lateral canals become somewhat narrower,
until they altogether cease close up towards the terminal
polyp, owing to both the septa on each side becoming
fused together, so, that there are. then, only two canals,
namely, the dorsal and the ventral canals, of which, the first
becomes narrower and narrower, until, also, it ceases a
few millimetres distant from the terminal polyp. The
ventral canal, which .is still, tolerably wide; and in which the
axis terminates; makes a sharp curve under the terminal
polyp; then becomes considerably reduced in width, and
terminates on the ventral side, 4—5""" below the base of
the terminal polyp, in a round perforated papilla.
In the bulbous part of the stalk, the 4 longitudinal
canals experience, only, very little change; whilst, on the
other hand, the 4 septa are remarkably modified, and a
septum-transversalc appears. About 10’"’" from the base
of the stalk, the ventrolateral septum becomes divided
on each side, in two longitudinal folds; the posterior fold
(Hg. 32 ft), proceeds to insert itself along the lateral part
of the sheath of the axis, right down to it’s extremity,
round which it entwines itself; and, it becomes, here,
concreted with the corresponding fold from the other side
(Hg. 33, a). The other, anterior fold (Hg. 32. b), which
is the thickest one, proceeds diagonally, downwards and
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