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30
Omkring Munden har den en brunrød King. Dyret kryber
paa Tentaklerne.
Hudens histologiske Bygning afviger ikke væsentlig
fra Holothuridernes i Almindelighed. Den dannes af en
fuldkommen gjennemsigtig og strukturløs Cuticula. Fig. 2, a,
under hvilken et Lag Cylinderepithel, Fig. 2, b, der støder
umiddelbart til et tykt, hyalint Bindevævslag. Fig. 2. c,
hvortil Muskelhuden (Tvær- og Længdemuskler) er fæstet.
Hele Kroppens indre Flade er beklædt med et flimrende
Peritoneum.
Det hyaline Bindevæv er overortjentlig rigt paa
for-skjelligtforinede Legemer, der ere snart ovale med en eller
to Udløbere, Fig. 2, d, snart ere de mere eller mindre
forgrenede, saaledes at de lange fine Udløbere korrespondere
med Grene fra andre lignende Celler, hvorved et fint
Netværk oftere fremkommer. Fig. 2, e. Disse samtlige Celler
have en Kjærne, der ikke er meget stor, og som er omgiven
af et tyndt Lag Protoplasma.
En saadan Rigdom af forgrenede Bindevævslegemer
have vi ikke tidligere stødt paa; vi vare i Begyndelsen
tilbøjelige til at antage dem for Nerveceller ; men nærmere
Undersøgelser bragte os fra denne Antagelse ; thi de havde
ikke Nervecellens egentlige Karakter; Kjernen var meget
for liden og Protoplasmaindholdet for fattigt, og det var os
ikke muligt at sætte dem i nogensomhelst Forbindelse med
de Nervetraade, vi fandt i Huden. Dr. Théel har i sine
Bemærkninger til Myriotrochus fundet lignende Legemer i
Huden, som hau antager for Nerveceller, men vi ere ikke
langtfra at tro, at dehne Antagelse hviler paa
^^Misforstaaelse.
I Bindevævslaget, indenfor Epithelet. men beklædtjaf
dette, findes de tidligere omtalte Hjul jleirede,fFig. 2, /.
Med Hensyn til disse have vi kun lidet at føie til
Steen-strup’s Beskrivelse. Den Flade, der vender udad, er
skaal-formig fordybet, og Centrumet, hvorfra Radierne udgaa,
danner en liden, rund, knopformig Fremstaaenhed. der er
forsynet med smaa Pigge, Fig. 2r g. Det er til denne Del,
at det Bindevævsbaand er fæstet, som danner Stilken.
Radierne variere i Antal; det samme er Tilfældet med de
paa Hjulperipherieu anbragte Tapper, Fig. 2, h, eller
Tænder, der altid ere tilstede i større Mængde, hvilket gjør,
at de snart sidde imellem to Radier, snart lige paa dem.
Den bredere Del af Tappen er paa sin^ydre Flade forsynet
med et afrundet Indsnit, Fig. 2, i, hvilket bidrager til at
give Hjulets Peripheri en undulerende Form, saaledes som
af Dr. Théel antydet.
Foruden Bindevævslegemerne findes hist og her i
Corium et intens brunrødt Pigment, dels i Klumper, dels
indesluttet i særegne Celler. Ringmusklerne ere ikke
afbrudte af Længdemusklerne eller Nervestammerne, men gaa
rundt Legemet og dække Radialnerverne, der altsaa ligge
imellem dem og Huden.
Paa Kroppens indre Flade, op imod Kalkringen, findes
en Mængde yderst smaa, fritstaaende Legemer, der have en
noget forskjellig Form, men hvoraf Bladformen er den
Round the mouth it has a brown-red ring. The organs of
motion are the tentacles, on which the animal creeps.
The histological structure of the skin does not differ
essentially from that in other Holothurians. Underneath
the cuticle, which is translucent and structureless, fig. 2. a,
extends a layer of cylindric cellular epithelium, fig. 2. b,
connate with a thick hyaline layer of connective tissue,
fig. 2, c, webbed to the muscular integument (consisting of
transverse and longitudinal muscles). The entire inner
surface of the body is clothed with ciliated peritoneum.
The hyaline connective tissue has dispersed
throughout it numbers of corpuscles, varying in form, some oval,
with one or two prolations. fig. 2. d, some more or less
branched, the long, slender ramifications corresponding with
those from other similar cells, and thus frequently
constituting an intricate network, fig. 2. e. The cells have all of
them a nucleus, not very large, which is invested with a
thin layer of protoplasma.
Such an abundance of ramifying corpuscles we have
never before met with in the connective tissue; indeed, we
were at first disposed to regard them as nervous cells: but
on further examination, the falsity of this assumptive view
soon became apparent: for these corpuscles have none of the
characters peculiar to a nervous cell; the nucleus is much
too small, the protoplasmatic contents are too meagre, and we
failed to discover any connexion whatever with the nervous
filaments observed in the skin. True. Dr. Théel. as
appears from his notes on Myriotrochus, has observed similar
corpuscles in the integument, which he takes to be nervous
cells; but we are almost afraid he lias been misled in
putting forward such an assumption.
In the layer of connective tissue, underneath the
epithelium, are imbedded the rotated calcareous corpuscles
mentioned above, fig. 2, f, with regard to which we have
but little to add to Professor Steenstrup’s description. The
exterior surface is calyx-shaped, and the central point from
which the radii proceed constitutes a small, round,
tubercular apophysis, furnished with minute spinules. fig. 2. g.
It is to this part that the membranous ligament forming
the stem is attached. The radii vary in number; the same,
too, is the case with the cogs or teeth, fig. 2. h, on the
periphery of the rotated corpuscles, which, being very
numerous, occur sometimes between the radii, sometimes on
them. The broad part of the cog, or tooth, has on its
outer surface a rounded incision, fig. 2,», which, as noticed
by Dr. Théel, helps to give an undulary form to the
periphery of the rotated corpuscle.
Exclusive of the corpuscles of connective tissue, occurs
every here and there in the corium a deep brownish-red
pigmentary substance, either in isolated lumps or deposited in
peculiar cells. The annular muscles are not decussated by
the longitudinal muscles or the nervous trunks, but encircle
the body, covering the radial nerves, which extend
accordingly between the annular muscles and the skin.
On the inner surface of the body, in close proximity
to the calcareous ring, are seen numbers of exceedingly
minute isolated corpuscles, varying somewhat in form, which,
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