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68
imellem Armvinkelen og Analaabningen, kun fjernet 5mn
fra denne, Fig. 8, 9.
Saavel Ryg- som Bugfladen er besat med yderst fine,
noget spredte Pigge, der kun kan iagttages med en stærk
Loupe, Fig. 12. Paa Rygsiden, hvor de afbrydes af en
Mængde større og mindre Grupper Tentakelporer, ere de
mindre end paa Bugfladen, hvor der sees flere fine,
paa-langs gaaende Furer, Fig. 10. 11.
De 5 Arme ere temmelig flade, brede ved Basis;
henimod deres noget afstumpede Spids blive Tentakelporerne
yderst sparsomme, imedens Piggene her staa tættere sammen.
Bugfuren er smal, forsynet med 2 Rækker Fødder
uden Spikler, samt en Række Pigge paa hver Side,
saaledes at to og to staa sammen og gribe ind i de tilsvarende
paa den modsatte Side, Fig* 10, a. 11, a. Udenfor
Ambulacralfuren er der 3 Rækker Pigge, hvoraf de, som staa
i den inderste Række, ere ligesaa lange som
Furepapillerne, men have en bredere Basis. Disse Pigge have en
noget særegen Stilling, idet de danne korte, transversale
Rader med 3 i hver Rad; i en enkelt Rad sees ogsaa 4 Pigge,
Fig. 10, b. 11, b.
Mundaabningen lukkes af to temmelig lange, stærke
Tænder; paa Kjævernes Rand 2—3 store Pigge, Fig. 10, c.
Interbrachialrummene ere besatte med fine Pigge, der
indimod Mundvinkelen blive noget større og staa mere
isolerede, Fig. 10. 11.
Søstjernens Rand er temmelig skarp og dannes af de
ventrale Randplader, der bære fra 3 indtil 6 Pigge, Fig.
11, c. De dorsale Randplader neppe synlige, førend
Exemplaret var tørret; men da bleve de meget tydelige.
Saavel af disse som af de ventral Randplader udgjør
Antallet 38.
Hudskelettet er paa Rygfladen dannet af
Kalkstykker, der have en noget forskjellig Form. Paa Skiven ere
de ovale, have en lidt hvælvet Overflade, der bærer
Piggene, imedens Underfladen er stærk konkav, Fig. 13. Disse
Kalkplader støde tæt til hverandre, yderst sjelden ligger
den ene Rand over den andens, og kun mellem deres
Siderande er der et lidet Rum, hvori sees en eller flere
Tentakelporer. De danne et Net med yderst smaa Masker.
Paa Armene ere Kalkstykkerne mere langstrakte,
ligge endnu tættere sammen, hyppigere taglagte, danne
spines. The madreporite is circular, and is seated in a
cavity in the integument, situated, between the
interbrachial angle and the anal aperture; distant only 5mm
from the last named (figs. 8, 9).
Both the abactinal and the actinal surfaces, are beset
with extremely slender, somewhat scattered spines, which
only become visible, when submitted to a powerful
magnifier (fig. 12).
On the abactinal surface; where they are displaced
by a multitude of larger and smaller groups of tentacular
pores; the spines are smaller them on the actinal surface,
upon which, several minute longitudinal furrows are seen
(figs. 10, 11).
The five rays are rather flat, and broad at their
origin; and towards the somewhat blunted tip, the
tentacular pores become extremely scarce; whilst, the spines
become in this situation, more closely set.
The ventral furrow is narrow, and is furnished with two
series of suckers free from spiculæ; and also, with a row
of spines on each lateral margin, arranged two and two
together, in such manner, that they interlace with the
corresponding spines of the opposite margin (figs. 10, a. 11, a).
Outside the ambulacral furrow, there are 3 series of spines;
of which, those situated in the inmost series are as long
as the furrow papillæ, but have a broader base. These
spines are somewhat peculiarly placed; in as much, that
they are arranged in short transverse series containing 3
spines in each series, but in an occasional series, however,
4 spines are sometimes to be seen (figs. 10, b. 11, b).
The oral aperture is closed by two pretty long strong
teeth, and on the margin of the jaws 2—3 spines occur
(fig. 10, c).
The interbrachial spaces are beset with slender spines;
which, in towards the oral angle, become somewhat larger,
and stand more isolated (figs. 10. 11).
The margin of the starfish is rather sharply defined,
and, is formed by the ventro-marginal plates, which carry
from 3, up to 6 spines (fig. 11, c). The dorso-marginal
plates were scarcely perceptible until after the specimen
was dried, but then they became quite distinct. Both the
ventro-marginal, and dorso-marginal series of plates, are
alike in number, having each 38 plates.
On the abactinal surface, the integumental skeleton
is formed of calcareous ossicles having a somewhat
varying form. The ossicles of the disk are ovate, and have a
slightly arcuate superior surface, which carries the spines,
whilst, the inferior surface is strongly concave (fig. 13).
These calcareous plates butt close to each other, and, very
rarely, does the margin of one plate imbricate upon the
other plate; and only between the lateral margins, is there
left a small interspace, in which one or more tentacular pores
are visible. The calcareous plates form a reticulation,
having extremely small meshes.
Upon the rays, the calcareous ossicles are more
elongated, and lie still closer together, besides which, they more
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