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29
thurier i det kariske Hav1 omtalt Myriotrochus Rinkii, men
da vi formene, at det er en anden Art, sandsynligvis
Huxley’s Chirodota brevis, han har havt for sig, og ikke Rinkii,
hvilket vi senere skulle godtgjøre, saa have vi ikke optaget
Théels Myr. Rinkii i Synonymien.
Myr. Rinkii, St.
(Fig. 1).
Legemet næsten cylindrisk, lidt mere hvælvet paa
Mygsiden og lidt smalere mod den bagerste, afrundede Ende,
hvor den runde Analaabning lindes, — er 10"" tykt og
60"" langt, foruden Tentaklerne, der ere 4"" lange. Disse
ere 12 i Antal, ikke retraktile, forsynede med 4—6 Cirrer
paa hver Side, foruden Midtcirren, der er den længste,
Fig. 1. Mundaabningen rund. omgiven af en Vold. Huden
er klar gjennemsigtig, saa at baade Muskulaturen
(Tvær-og Længdemuskler), Kalkringen, Tarmkanalen og
Genera-tionsorganerne kunne tydelig sees.
Paa Ryggen iagttages mange Kalkhjul, der viser sig
at være stilkede, saa at naar Dyret under Bevægelsen
trækker sig noget sammen, rage Hjulene et godt Stykke udover
Hudens Overflade. Paa Ryggen findes Hjulene i de to
intermuskulære Felter, hvor der er omtrent 12 paa hver
Kvadratmillimeter; de staa dog langtfra regelmæssigt, og
ere midt paa Ryggen meget mere spredte, saa at der
kommer neppe 10 paa hver Kvadratmillimeter. Paa Bugfladen
derimod ere de saa overordentlig spredte, at det endog har
sine store Vanskeligheder at opdage et og andet, og paa
mange Exemplarer var det ikke muligt at iagttage et eneste
Hjul.
Den bagerste Del af Tarmen (den sidste Slynge) har
et temmelig lige Løb og udvider sig saagodtsom ikke, idet
den ender i den runde Anus. Der er ingen Kloak, nogen
rythmisk Udvidning af Analaabningen finder ikke Sted;
denne aabnes kun, naar Excrementerne skulle udstødes.
Tarmens indre Flade er beklædt med et Lag af temmelig
storkjærnet. flimrende Cylinderepithel; Cellerne vare fyldte
med et yderst finkornet Protoplasma. I Tarmindholdet
findes hos de allerfleste (og vi have havt Anledning til at
se en Mængde i levende Live) mange smaa, rødlige
Planarier, der vare meget livlige i deres Bevægelser. Efterat de
vare komne ud af Tarmen, vare Bevægelserne særdeles
raske, og de levede meget godt i Søvandet.
Myriotrochus Rinkii har en svag brunligrød Farve
. paa Kroppen; Tentaklerne ere noget mørkere med en intens
mørk, brunrød, lidt aflang Pigmentplet paa Cirrernes Spids.
inhabiting the Kara Sea,1 mentions Myriotrochus Jjtinkii,
but the animal he alludes to belonging, as we conceive,
to another species, probably Huxley’s Chirodota brevis, and
not Rinkii — our reasons will be given in due course —
we have not included Théel’s Myr. Rinkii in the list
of synonyms.
Myr. Rinkii, St.
(Pipr. l).
The body, which is almost cylindric, being but a trifle
more convex on the dorsal surface, and somewhat slenderer
at the posterior rounded extremity, where the circular anal
aperture occurs, has a thickness of 10"" and a length of
60"", exclusive of the tentacles, which are 4"" long. The
latter, 12 in number, are non-retractile, and furnished on
either side with from 4 to 6 cirrhi, exclusive of the medial
cirrhus, which is the longest, fig. 1. The oral aperture
round, and surrounded by a ridge. The skin is in a high
degree translucent, the muscles (transverse and longitudinal),
the calcareous ring, the intestinal canal, and the generative
organs being distinctly seen through it.
Disposed over the dorsal surface, are numbers of
rotated calcareous corpuscles, which, being pedunculate, ,
project some distance above the surface of the integument,
when the animal, in moving, slightly contracts its body.
On the back, these rotated corpuscles occur dispersed
over two intermuscular spaces, about 12 to every square
millimetre; their arrangement is however anything but
regular, and in the middle of the dorsal region less close,
scarcely 10 to every square millimetre. On the ventral
surface, they are so scattered and so few in number that
you find it difficult even to light on one here and there;
nay, in many specimens not a single rotated corpuscle
could be detected.
The posterior portion of the intestine (the last
circumvolution) takes rather .a straight course, and scarcely
expands at all, terminating as it does in the round anal
aperture. There is no cloacum, no rhythmic expansion of
the anus, which does not open save for the discharge of
the fæces. The inner surface of the intestine is clothe^
with a layer of ciliated nucleal epithelium, the cylindric
cells being filled with an exceedingly fine granulous
protoplasma. The contents of the intestine, in the great majority
of individuals (and we have had opportunity of observing a
very large number of living specimens), exhibits numerous
small reddish Planarice, moving about with great vivacity.
Out of the intestine, in particular, their motions were verv
lively, and the sea-water did not affect them injuriously.
On the body, Myriotrochus Rinkii is of a pale
brown-ish-red; the tentacles are somewhat darker, with a slightly
ovate patch of deep browny-red on the poirits of the cirrhi.
1 Note sur quelques Holothuries des mers de la Nouvelle Zemble
par Hj. Théel. Upsala 1877.
1 Note sur quelques Holothuries des mers de Ia Nouvolle Zemble,
par Hj. Théel. Upsala 1><77.
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