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103
mentlig med et yderst interessant phylogenetisk Phænomen
at gjøre, nemlig: at Søstjernen udvikler sig af
Cri-noiden.
Vi antage, at en mere indgaaende anatomisk
Undersøgelse skulde have frembragt endnu flere
Eiendommeligheder end de, vi have kunnet angive; men vi have ikke
villet odelægge det eneste Exemplar, som findes og have
derfor maattet opgive at undersøge nærmere Rygappendixet
og Hudskelettet m. m.
Slægtskarakter.
Legemet 5-armet. Rygsiden beklædt med Paxiller.
Fra Ryggens Centrum reiser sig et langt, cylindrisk
Appendix, beklædt med Pigge. Ingen Anus. 2 Rækker
konisk tilspidsede Fødder.
ably, concerned with an extremely interesting phylogenetic
phenomenon viz. that the starfish is evolved from the
Crinoidea.
We believe that a more minute anatomical
examination, would, probably show, still other peculiarities, besides
those, which we have been able to state here, but we
have been unwilling to destroy the only existing specimen,
and have been obliged, therefore, to relinquish a more
minute examination of the dorsal appendix, and the dermal
skeleton &c. &c.
Generic character.
The body 5-rayed. The abactinal surface clad with
paxillæ. In the centre of the disk, there projects a long
cylindric appendix clad with spines. No anus. 2 series
of conical acuminate suckers.
Efterat denne Afhandling med Tavler i længere Tid
har ligget færdig til Trykning, udgjørende en Fortsættelse
af den i Norsk Magazin for Naturvidenskaberne XXVII
Bind, 3. Hefte, paabegyndtc Afhandling „Fra den norske
Nordhavsexpedition", og hvori 1 lyaster er opregnet, — ere
vi blevne bekjendte med en Beretning af Professor Edm.
Perrier i Comptes Rendus No. 26 (26 Decbr. 1882) „Sur
une Astérie des grands profondeurs de l’Atlantique,
pour-vue d’un pédoncule dorsal."
Paa Travailleur-Expeditionen i 1880 er der funden
2 Exemplarer af en lille Søstjerne forsynet med en
Dor-salstilk, hvilken Perrier har kaldet Caulaster pedunculatus.
Hos det mindste af disse to Exemplarer har han paavist,
at ved Basis af Rygappendixet (Stilken) er der to Kredse
af Plader lig dem, der efter Professor Lovéns
Undersøgelser danner Periproctet hos Echiniderne, og hvorved de
nærme sig Crinoidernes Calyx. Hos det noget ældre
Exemplar vare disse Plader forsvundne. Paa vor Ilyaster,
der er meget større end Perriers største Exemplar,
saaes heller ikke saadanne Plader; men vi have, som
tidligere anført, ikke kunnet foretage nogen dyberegaaende
Undersøgelse med Hensyn hertil. Perrier antager, og med
god Grund, at hans Caidaster danner et Bindeled imellem
Grinoiderne og Asteriderne, og vore Iagttagelser over
Ilyaster stadfæste end mere denne Antagelse. Efter saavel
Perrier’s som vore nu gjorte Observationer synes det med
temmelig Bestemthed at fremgaa, at i Echinodermernes
Udviklingsrække ere Grinoiderne de ældste og Asteriderne
yngre; forøvrigt henvise vi til ovennævnte, yderst
interessante Meddelelse i Comptes Rendus.
Since the preparation of this Memoir (it has lain a
considerable time ready for the press) which forms a
continuation of the paper „Fra den norske Nordhavs
Expedition", published in Norsk Magazin for Naturvidenskaberne
XXVII Bind, 3die Hefte, and in which Ilyaster is
included ; we have become acquainted with a Report by
Professor Edv. Perrier in Comptes Rendu No. 26 (26 Decbr.
1882) „Sur une Astérie des grands profondeurs de
l’Atlantique pourvue d’un pédoncule dorsal."
During the Travailleur-Expedition in 1880, two
specimens of a small starfish were found, which were furnished
with a dorsal peduncle, and which Perrier has called
Caidaster pedunculatus. He has shown, that at the base of the
dorsal appendix (the peduncle) in the smallest of these
two specimens, there are two rings of plates, like those,
which according to Professor Lovéns observations form
the periproct in Echinodermata and in this feature, they
approach to the chalice in Crinoidea. In the somewhat
larger specimen these plates had disappeared. Neither, in
our Ilyaster, which is so much larger than Perrier’s
largest specimen, were any such plates to be seen, but, as
already stated, we have not been able to institute a minute
examination in regard to them. Perrier supposes, and with
good reason, that his Caulaster forms a connecting link
between Crinoidea and Asteroidea, and our observations on
Ilyaster still further confirm this supposition. From both
Perrier’s and our later observations, it appears, with a
considerable degree of certainty, that in the Echinodermata’s
stages of development, the Crinoidea represents the oldest,
and the Asteroidea represents the youngest stages in the
process; but we refer the reader to the above named,
extremely interesting communication in Comptes Rendus.
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