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70
Hudskelettet paa Ryggen bestaar af smaa, ovale
Kalkplader, som danne et massivt Net med yderst smaa Masker; paa
Bugfladen aflange, flade Kalkplader, der danne Rækker og
ere taglagte. Ingen Pedicellarier, ingen Spikier i
Ambu-lacrerne.
Artskarakter.
Forholdet imellem den lille og store Radius som 1 :
l2/3. Paa hver Adambulacralplade 5 Pigge, hvoraf 2 vende
indad i Bugfuren og danne 1 Række paa hver Side; de
øvrige 3 danne 3 Rækker udenfor Bugfuren. De ventrale
Randplader bære 3—6 korte, stumpe Pigge.
Madreporpladen nedsænket i den tykke Hud.
Ryggen rosenrød, Bugen gulrød.
Som det ril sees, have vi af denne Søstjerne dannet
en ny Slægt, og vi skulle nu angive vore Grunde derfor.
Ved første Øiekast skulde man tro, at man her havde med
en Porania at gjøre; men en nærmere Undersøgelse peger
næsten ligesaameget hen paa Slægten Asterina som paa
Porania. Den tykke, tilsyneladende glatte Hud, de store,
ventrale Randplader, den skarpe, piggede Rand, der dannes
udelukkende af de ventrale Randplader, — Alt dette har
den aabenbart tilfælles med Porania; men saa adskiller den
sig fra denne derved, at saavel Ryg som Bug er overalt
besat med fine, enkeltstaaende Pigge, at’Hudskelettet
danner paa Rygfladen et tæt, massivt Maskenet, bestaaende af
smaa, ovale Kalkstykker, — en Eiendommelighed, hvorved den
nærmer sig Slægten Asterina.
Den staar saaledes efter vor Formening imellem de
to nævnte Slægter uden egentlig at tilhøre nogen af dem,
og derfor have vi fundet det rettest at danne en ny Slægt
for den.
Pteraster militaris, (O. Fr. Müller) Müller & Troschel.
Tab. XIII, Fig. 18, 19.
1776. Astetias militaris, O. Fr. Müller. Zool. Dan. Prodr.
pag. 234, No. 2828.
1778. Asterias militaris, Gmelin. System Nat. Linn. edit.
XII, pag. 3160.
1806. Asterias militaris, Ratke. Zool. Dan. Vol. IV, pag.
13. Tab. 131.
is sharply defined, and formed solely by the
ventro-marginal plates, furnished with spines. The abactinal dermal
skeleton consists of small oval calcareous plates, producing
a massive reticulation with extremely small meshes. On
the actinal surface the dermal skeleton consists of long
flat calcareous plates which form imbricate series. There
are no pedicellariæ. No spiculæ on the suckers.
Specific Character.
The disk radius bears to the brachial radius the
proportion of, as 1 : l2/3. On each ambulacral plate, there are
5 spines, of which, 2 turn towards the ventral furrow, and
form a series on each of its lateral margins, whilst the
remaining 3 spines, form 3 series outside the ventral
furrow. The ventro-marginal plates carry 3—6 short blunt
spines.
The madreporite is found, depressed in the thick
integument. The abactinal surface is rose coloured. The
actinal surface is orange coloured.
It will be observed that we have formed a new genus
for this starfish; and we shall now state our reasons for
doing so.
A superficial examination of this starfish, might lead
us to suppose, that we were, here, concerned with a
specimen of the genus Porania, but a closer examination,
points almost as much to1"the genus Asterina. The thick,
apparently smooth integument; the large ventro-marginal
plates; the sharply defined spine-clad margin, formed by the
ventro-marginal plates exclusively, are undoubtedly, features
common to Porania and Asterina; but it differs from
Porania in this; that both the abactinal and actinal surfaces,
are everywhere, beset with slender solitary spines; and
further, that the dermal skeleton forms on the abactinal
surface, a close massive reticulation, composed of small, oval
calcareous ossicles, a peculiarity in which it approaches to
the genus Asterina.
It takes its place therefore, in our opinion, between
the two genera referred to, without really belonging to
either of them; and we have therefore considered it worthy
of being assigned to a new genus.
Pteraster militaris, (O. Fr. Müller) Müller & Troschel.
Tab. XIII, fig. 18. It).
1776. Asterias militaris, 0. Fr. Miiller. Zool. Dan. Prodr.
pag. 234, No. 2828.
1778. Asterias militaris, Gmelin. System Nat. Linn. edit.
XII, peg. 3160.
1806. Asterias militaris, Ratke. Zool. Dan. Vol. IV, pag.
13, Tab. 131.
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