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meget stærke. Udenpaa Ringmuskellaget er
Peritoneal-beklædningen bunden ved Bindevæv.
Spiserørets og Tarmens Vægge ere noget forskjellige
fra Svælgets. Epithellaget, der beklæder den indre Flade,
er temmelig bredt og dannes af meget lange Cylinderceller,
hvis bredere Del vender mod Tarmhulheden. Mangfoldige
af disse Cylinderceller vare fyldte med en finkornet,
gul-agtig Protoplasmamasse, og adskilte sig fra de andre, der
vare ganske vandklare og havde et mere grovkornet
Indhold. Om disse gulagtige Cylinderceller fungere som Kjerfc
ler, der afsondrede den- store Mængde Slim, som
sammen-kittete Tarmindholdet, skulle vi ikke afgjøre med nogen
Bestemthed, ihvorvel det forekommer os sandsynligt. Dette
Slim var altid i størst Mængde tilstede i den egentlige
Tarm. hvor den paa enkelte Exemplarer dannede ligesom
et membranøst Overtræk, der formentlig var dannet af det
i Alcohol coagulerede Slim.
I det omtalte membranøse Overtræk saaes en stor
Mængde yderst fine, lange Folder, der havde en saa
skuffende Lighed med lange Haar eller Cilier, at vi i
Begyndelsen antoge dem derfor, en Antagelse, der tilsyneladende
var begrundet i den Omstændighed, at Prof. Ehlers i sit
Arbeide over Slægten Priapulus1 beskriver netop
enChitin-hud paa Tarmfladen, hvorfra mange fine, stive Haar udgaa.
Epithellaget, der paa sin indre Flade synes at være
forsynet med Cilier, er fæstet til et stærkt Bindevævslag,
Fig. 10, b. der sender listeformige Forlængelser ind i
Epi-thelet og danner derved de paa den indre Væg af saavel
Spiserøret som Tarmen fremragende Folder, Fig. 10, c.
Disse Bindevævslister ere rigere paa Bindevævslegemer, end
det øvrige Bindevæv. Udenpaa Bindevævet er nu
Muskelhuden med sine to bestemte Lag, nemlig Længde- og
Ringmuskler, hvilke sidste ere bundne til Peritonealovei’trækket
ved et smalt Bindevævslag.
Centralnervestrængen løber langs Midten af Bugfladen,
Fig. 1, a, ikke som hos Gephyreerne ialmindelighed paa
dennes indre Flade; men i Hudens Bindevæv, imellem
Muskel- og Epithellaget. Fig. 3, k. Hvor Nervestammen
ligger, er det fibrillære Bindevæv stærkt udvidet og omgiver
den paa en. beskyttende Maade, Fig. 3, c.
Centralnervestrængen er indesluttet i en tyk
Binde-vævsskede, Fig. 3. I, der sender en Forlængelse .fra den
ene Væg til den anden, tvers igjennem Nervestammen, Fig.
3, m. Denne bliver derved delt i to Dele, hvoraf den
indre er bredest, Fig. 3, n, og har en lidt mørkere Farve.
Saavel fra denne Skillevæg, som fra Skedens indre Flade
1 E. Ehlers. Ueber die Gattung Priapulus. Zeitschrift f. wiss.
Z.oologie. 11 Band, pag. 205.
Den norske Nordhavsexpedition. Danielssen og Koren: Gephyrea.
muscular integument, which consists of longitudinal and
annular muscles, exceedingly strong. The peritoneal tunic
is webbed on to the layer of annular muscles by
connective tissue.
The walls of the oesophagus and the intestine differ
slightly from those of the gullet. The epithelial layer
investing the inner surface is comparatively broad, and consists
of exceedingly long cylindric cells, with the broader
portion facing the intestinal cavity. Many of these cylindric
cells were full of a finely granulous, ye’lowish
protoplasmatic mass, and differed from the others, which were
perfectly hyaline, and contained a more coarsely granulous
substance. Whether these yellowish cylindric cells serve
the purpose of glands, whose function is to secrete the
abundant supply of mucus that glues together the
contents of the intestine, we shall not venture to decide, though
such, we conceive, is highly probable. Most of this mucus
was met with in the intestine itself, where, in some of the
specimens, it actually formed a kind of membranous tunic,
the mucus having probably been coagulated by the action
of the alcohol.
In this membranous tunic were seen a great number
of long and exceedingly narrow folds, presenting so illusive
a resemblance to long capillaments, or cilia, that at first
we regarded them as such; and more especially, since
Professor Ehlers, in his Memoir on the genus’ Priapulus,1
describes such a chitinous membrane on the surface of the
intestine, from which proceed numerous stiff, slender capillaments.
The epithelial layer, which would appear to be
furnished, on its inner surface with vibratile cilia, is webbed
to a layer of strong connective tissue, fig. 10, b, from which
cornice-like prolations of connective tissue are produced into
the epithelium, thus occasioning the prominent folds, fig. 10,
c, on the inner wall of both the oesophagus and the
intestine. These cornice-like prolations are more abundantly
furnished with corpuscles of connective tissue than any
other part of the connective membrane. Next above the
connective tissue comes the muscular integument, with its
two layers of longitudinal and annular muscles, the latter
webbed to the peritoneal tunic by a narrow layer of
connective tissue.
The central nervous chord protends along the middle
of the belly, fig. 1, a, not on the inner surface, as in most
of the Gephyrea, but in the connective tissue of the skin,
between the muscular and epithelial layers, fig. 3, k. Round
the nervous trunk; the fibrillous connective tissue, which
invests it with a protective covering, fig. 3, c, is greatly
distended.
The central nervous chord is enclosed in a thick
membranous sheath, fig. 3, I, which sends a filament from
one wall to the other, piercing the nervous trunk, fig. 3. m.
Hence the latter is divided into two sections, the inner, of
a darker colour, being the broader, fig. 3. n. Both from
this partition-wall and from the inner surface of the sheath,
’ E. Ehlers. Ueber die Gattung Priapulus. Zeitschrift f. wiss.
Zoologie. 11 Band, pag. ’205.
3
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