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12
nemlig paa den Rand, der vender indad mod
Ambulacral-furen, og som hviler paa de egentlige Ventralplader, Fig. 2, b.
Udenfor denne Række tindes de dorsale Randplader, Fig. 2, c,
der ere noget større og korsformede; den indre Arm af
Korset lægger sig paa den ydre Arm af en tilsvarende
ventral Randplade. Enhver af disse Plader bærer en stærk
Pig, der tidligere er beskreven.
Bugfladens Hudskelet bestaar kun af en eneste
Længderække Plader, Fig. 2, b. Disse ligge med deres afrundede
Ender taglagte paa hverandre, ere langstrakte, smale,
næsten elliptiske med en undre (ydre) Flade, der er lidt
kon-vex, og som støtter de ventrale Randplader, og en øvre
(indre) Flade, der er lidt konkav, og som hviler paa den
undre, runde Rand af Adambulacralpladerne. Denne Række
af Bugplader strækker sig fra Armens Spids lige op i
Armvinkelen, hvor Randpladerne fra 2 Arme støde sammen;
thi andre Bugplader, hvormed de kunne forene sig,
saaledes som Tilfældet er hos Asterias rubens, Forbesii, vulgaris
og mange Andre, findes ikke. Paa yderst faa af disse
Bugplader (2—3 i den hele Række) fæster der sig en
temmelig lang Pig, som tidligere er omtalt.
Skelettet, Ambulacral- og Adambulacralpladerne,
frembyde intet særegent. Adambulacralpladerne bære
afvexlende 1 og 2 Pigge, hvilke ere stillede saaledes, at Piggen
paa den Adambulacralplade, der kun bærer en saadan, staar
ligeoverfor Insertionen af de to Pigge paa hver af de
tilstødende to Adambulacralplader, hvorved det faar et
Udseende, som om der er 3 Rækker Ambulacralpapiller. Det
sande Forhold kommer først frem ved at isolere
Adambulacralpladerne. Et saadant Forhold findes ogsaa hos
Asterias rubens og Forbesii, imedens det ikke finder Sted hos
Asterias vulgaris.
Farve. Ryggen teglstensrød med hvide
Pedicellarie-krandse omkring Piggene. Bugen hvid.
Pindested.
Station 280, Beeren Eiland.
Art8karakter.
Legemet 5-armet. Forholdet imellem den lille og
store Radius som 1 : 6. Ryggen besat med korte, tykke,
tætstaaende Pigge, omgivne med 2—3 ovenpaa hinanden
staaende korsformede Pedicellarier. Paa Armenes Midte
og paa deres Sider staa Piggene i regelmæssige Rækker.
Imellem Piggene 1—3 Tentakelporer i den nøgne Hud. 2
Rader Ambulacralpapiller. Farven teglstensrød.
De to beskrevne Søstjerner, nemlig Aster, spitsbergensis
og Aster, hyperborea, have vi henført til den paa Arter saa
overordentlig rige Slægt Asterias, omendskjønt de, baade i
hvad ydre Habitus angaar og Hudskelettets Bygning, nærme
nearest the ventro-marginal plates (fig. 2, a), are not quite
cruciform, in as much as, that they want an arm on the
margin which faces inwards towards the ambulacral furrow
and rests on the ventral plate proper (fig. 2, b). Outside
this series, the dorso-marginal plates occur; (fig. 2, c)
they are cruciform, and somewhat larger, and the inner
arm of the cross, overlaps the outer arm of a corresponding
ventro-marginal plate. Each of these plates carries a’
strong spine, which has been already described.
The ventro-dermal skeleton consists, of, only, one single
longitudinal series of plates (fig. 2, b). These lie with
their rounded extremities onerlapping each other, and are
narrow, elongate, almost elliptic in form, with a slightly
convex, inferior (outer) surface, which supports the
ventro-margjnal plate, and with a slightly concave, superior
(inner) surface, resting on the inner circular margin of the
adambulacral plates. This series of ventral plates, extends
from the extremities of the rays close up to the
inter-brachial angle, where the marginal plates of two rays meet;
because, there are no other plates found, with which they
could unite themselves, as is the case in Asterias rubensf
Asterias forbesii, Asterias vulgaris, and many others. On
extremely few of these ventral plates, (2—3 in the whole
series) a somewhat long spine which has been already spoken
of, is found attached.
The skeleton, and ambulacral and adambulacral
plates, present nothing worthy of note. The adambulacral
plates carry (alternately, 1 and 2 spines, so situated, that
the spine on the adambulacral plate which only carries
one, is situate opposite the insertion af the two spines on
each of the adjoining two adambulacral plates; which gives
an appearance, as if there were 3 series of ambulacral
pa-pillæ: the real state of the case becomes ’first apparent, on
isolating the adambulacral plates.
The same thing occurs in Asterias riibens, and Asterias
forbesii, whilst it does not occur in Asterias vulgaris.
Colour. — The abactinal surface is brick-red, with
white wreaths of pedicellariæ around the spines. The
actinal surface is white.
Habitat.
Bear, or Cherry Island. Station 280.
Specific character.
5 rayed starfish: the proportion between the
disk-radius and the brachial radius, is, as 1:6. The dorsal disk
is occupied by closely set, short, stout spines, environed by
2—3 wreaths of cruciform pedicellariæ, placed the one
above the other. Upon the rays, regularly formed, mesial,
and lateral, series of spines. In the bare integument
between the spines, 1—3 tentacular pores are found. 2 series
of ambulacral papillæ. Colour, brick-red.
We have assigned the two starfishes Asterias
spitsber-gensis and Asterias hyperborea which have now been
described, to the genus Asterias, already so rich in species,
although, both in regard to external habit, and construction
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