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23
sig til Ring- og Længdemusklerne.1
Fra Schmardas Iagttagelser afviger derimod vore
temmelig betydeligt; thi hverken have vi fundet fibrillært
Bindevæv, maskeformigt sammenvævet med Kar, eller
Kjer-telorganer. Vi ere tilbøielige til at betragte saavel de
enkelte, som de i Grupper i det hyaline Bindevæv
leirede-Celler, hvori indeholdes et yderst finkornet, grønligt
Pigment, for egne Pigmentceller, der vel i den ydre Hud ere
bundne til det hyaline Bindevæv; men som vi senere skulle
se træffes baade i fibrillært Bindevæv og i Muskellagene,
uden at de tilkjendegive sig som Kjertelorganer.
Fordøielsesorganerne.
Mundspalten, der gaar paalangs og er begrændset af
tykke muskuløse Læber, fører ind til en sækformig
Udvid-ning (Mundhulheden), som er 9fflm lang og omtrent 10mm i
Gjennemsnit paa det Videste; men smalner ’saa stærkt af,
at der, hvor den gaar over i Svælget, er den kun 3mm.
Denne Mundhulhed dannes af en rørformig Forlængelse af
den ydre Hud, og paa dens indre Flade sees flere stærkt
fremragende, temmelig brede, circulære Folder, der dog ere
mest fremspringende paa Rygfladen, og • hvoraf de to
nærmest Mundspalten ere de betydeligste. De aftage noget
imod Svælget.
Mundhulhedens Vægge bestaa åf de samme
Væv,-som Huden. Paa den indre foldede Flade iagttages et
tykt Lag Cylinderepithel (sandsynligvis flimrende), der rager
ind i Hulheden, og er især tykt paa de fremragende
Folder, som dannes af fortykket Bindevæv; udenfor
Epithellaget er et temmelig bredt fibrillært Bindevævslag, hvor
Fibrene anastomosere med hverandre, og hvori er leiret,
dels enkeltvis, dels spredte Grupper af de samme Celler
og Pigmenthobe, som findes i den ydre Hud. kun i en
rigeligere Mængde. Dette Bindevævslag støder umiddelbart til
Muskellaget, der bestaar af Ring-, Længde- og
Skraamusk-ler, og i disse Lag sees ogsaa de nysnævnte Celler og
Pigmenthobe, men sparsommere. Skraamuskellaget er beklædt
af Peritoneum.
Hele Mundhulhedens ydre Flade er ved en Mængde
stærke Bindevævstraade, hvortil enkelte Muskelfibre føie
sig, bunden til den forreste Del af Kropsvæggen. Der,
hvor Mundhulheden gaar over i Svælget, er paa den
ydre-Flade én meget stærk Indsnøring, og paa den tilsvarende
indre Flade er der en bred Fold, der rager cirkelformig
ind i Hulheden og danner en Slags Sphincter, idet den er
forsynet med stærke Ringmuskelfibre. Folden dannes af
fortykket Bindevæv.
1 Dr. J. W. Spengel har fundet ct Skraamuskellag overalt i
Huden hos Bonellia viridis. Mittheiluugen aus der zoologischen Station
zu Neapel, 1te B. 3te Heft, 1879.
that on the anterior portion of the body, oblique muscles
adjoin the annular and longitudinal layers.1
Meanwhile, Schmarda’s observations differ materially
from the results of our own examination; for neither did
we remark any fibrillous connective tissue interlaced with
vessels; nor any description of glandular organs. The
cells scattered throughout the hyaline tissue, whether
isolated or in groups, we are disposed to regard as special
pigmentary cells (they contain a minutely granulous,
greenish pigment), webbed indeed, in the outer skin, to the
hyaline connective tissue, but which, as will, afterwards
appear, are met with alike in the fibrillous tissue and in
the muscular layers, though not as glandulous organs.
Digestive Organs.
The buccal cleft, extending lengthwise, and margined
by thick muscular labiæ, passes into a sac-like expansion (the
buccal cavity), 9ram long and about 10mm in diameter where
it is thickest, but narrowing so rapidly as to measure, only
3mm in diameter at the gullet. This buccal canity is
the result of a tubular elongation of the outer integument;
and on its inner surface occur several broad, circular,
exceedingly prominent folds, most protuberant on the dorsal
surface, the two in immediate, proximity to the buccal cleft
being the largest. These folds become less salient in the
vicinity of the gullet.
The walls of the buccal cavity consist of the same
tissue as that in the. skin. On the inner, folded
surface, is seen a thick layer of cylindric epithelium
(probably furnished with vibratile cilia), which extends into the
cavity, and is thickest on the prominent folds, consisting
of inspissated connective tissue. Above the epithelial layer
lies a broadish layer of fibrillous connective tissue, with
anastomosing fibres, throughout which are dispersed,
isolated and in scattered groups, cells and amorphous lumps
of pigment, similar to those in the outer skin, only in
greater abundance. This layer of connective tissue directly
adjoins the muscular integument, which is built up of
annular, longitudinal, and oblique muscles; and these layers,
too, are furnished with the aforesaid cells and pigmentary
lumps, but more sjfciringly. The oblique muscular layer is
’ invested with a peritoneal tunic.
The entire outer surface of the buccal cavity is webbed
by numbers of strong filaments of connective tissue and a few.
muscular fibres to the anterior portion of the wall of the
body. At the commencement of the gullet, is seen on
• the outer surface of the buccal cavity a very deep
instric-tion, and on the inner surface occurs a broad foldj
projecting with a circular sweep into the cavity, ’ where it
forms a kind of sphincter, being furnished with strong
annular muscular fibres. The fold consists of incrassated
connective tissue.
1 Dr. J. W. Spengel has invariably observed a layer of oblique
muscles in the skin of Bonellia viridis. Mittheilungen aus der
zoologischen Station zu Neapel, lte B. 3te Heft, 1879.
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