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20
ker, Fig. 8, c, der forene sig med Kalknettet i Skivens
Omkreds.
Langs Midten af Armene er en Række store,
kors-dannede, taglagte Plader, som ere konvexe udad, hvor de
bære en Pig, og lidt konkave indad, Fig. 8, e; den ydre,
perpendikulære Forlængelse er meget lang, og til de korte
Tverforlængelser støde de før omtalte kortere eller længere
Kalkbjelker.
Mange af de ovenfor beskrevne Kalkstykker have paa
sin ydre Flade 1 eller 2, knopformige Forhøininger, i hvis
Midte er en rund Fordybning, hvori Piggen fæstes ved et
Ligament.
Paa Siden af Armen, der hvor Grændsen afstikkes
imellem Ryg og Bug ved den tidligere omtalte Pigrække,
sees indvendig paa Hudskelcttet en Rad korsdannede
Kalkstykker, Fig. 8,/. 9, der ligge med deres korte,
.perpendikulære Arme taglagte paa hverandre, strække sig fra
Skiven langs hele Armen til dennes Spids, aftagende i
Størrelse og bærende paa sin ydre Flade en stærk Pig. Disse
Kalkstykker kunne betragtes som dorsale Randplader.
Bugfladens Hudskelet bestaar af en Rad Kalkstykker,
der i Form nærme sig overmaade meget de nys ovenfor
beskrevne korsdannede. Disse Kalkplader støde med sin
indre, temmelig stumpe, fladtrykte Arm umiddelbart til
Adambulacralpladerne; de perpendikulære Arme ligge
taglagte paa hverandre, og den ydre (undre) Flade bærer 1,
stundom 2, • stærke Pigge, Fig. 8, g. Imellem disse to
Rækker korsdannede Kalkplader er der en Række aflange,
smale, lidt fladtrykte Kalkstykker, der fæste sig til de
nævnte korsdannede Pladers Tverarme og kunne ansees for
de ventrale Randplader, Fig. 8, h. Disse bære ingen Pig.
Ligesom Hudskelettet afviger noget fra det hos Asterias
glacialis og rubens, saaledes afviger ogsaa det egentlige
Skelet fra disse to Arter.
Ambulacralpladerne have temmelig lange, brede
Tver-processer, der med sin gaffelformige Ende ganske skjuler
Adambulacralpladerne. Disse ere smaa, fladtrykte, næsten
runde Skiver med en tvers afskaaren øverste Rand, som
omfattes af Ambulacralpladens gaffelformige Ende, og en
lidt afrundet, undre Rand, der bærer - 3—é Pigge
(Fure-papiller). Der er intet Interbrachialrum.
Odontophoren er temmelig kort, uden Apophyser, bred
indad mod Munden, smal udad med et Indsnit paa
Midten. Sidefladerne skraa.
Farven.
Ryggen mørk, teglstensrød. Bugen hvidgul.
abut radially, (fig. 8, c) and unite with the reticulation
within the diskal compass. .
Along the brachial mesial line, there is a series of
large, cruciform, imbricate plates, convex, externally, on
which surface they carry a spine, and slighly concave
internally (fig. 8, e). The exterior perpendicular
prolongation is very long, and, the shorter or longer calcareous rods
previously spoken of, abut on the short transverse
prolongations.
Many of the above described calcareous ossicles, have,
on their external surface, 1 or 2 knob-shaped
prominences, in whose middle there is situated a circular cavity,
in which the spine is secured by a ligament.
On the lateral surfaces of the rays, there, where the
margin between the abactinal and actinal surfaces is
defined by the series of spines previously spoken of, there
is visible inside the dermal skeleton, a series of cruciform
calcareous ossicles, (fig. 8,/. 9) placed with their short arms
imbricate upon each other, and extending along the whole
ray, from the disk to the point, diminishing gradually in
size, and carrying a stout spine on the external surface.
These calcareous ossicles may be considered to be
dorso-marginal plates.
The dermal skeleton of the actinal surface, consists of
a series of calcareous pieces, which, in shape, ’ approach
very closely, to the just lately described cruciform plates.
These calcareous pieces abut, by means of their inner,
rather obtuse, flattened arm, close to the adambulacral plates;
the perpendicular arms lie imbricate upon each other
and the exterior (inferior) surface, carries 1, sometimes 2
spines (fig. 8, g). Between these two series of cruciform
calcareous plates, there is a series of oblong, narrow,
slightly flattened, calcareous pieces, which attach
themselves to the cross-arms of the cruciform plates referred to,
and these may be considered to be ventro-niarginal plates
(fig. 8, h). These carry no spines. Just as the dermal
skeleton differs somewhat, from that of Asterias glacialis and
Asterias rubens, so also, does the skeleton-proper differ from
that of these two species.
The ambulacral plates, have, rather long, broad,
transverse processes, which quite conceal the adambulacral plates,
with their bifurcated extremities. These latter plates are
small, flattened, nearly circular disks, with a truncate
superior margin, which is included in the bifurcated extremity
of the ambulacral plates; and with a slightly rounded,
inferior margin, carrying 3—4 spines (furrow-papillæ). There is
no interbrachial space.
The Odontophore is rather short, and without
apophyses ; broad internally towards the oral aperture; narrow
externally; and having a medial groove; the lateral
surfaces sloping.
Colour.
Abactinal surface, dark brick-red. Actinal surface
whity-yellow.
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