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11
Bugfuren temmelig smal, er forsynet med to Rader
Papiller, som ere fladtrykte, lange; i den inderste Rad ere
de længst, og have paa deres ydre, øverste Halvdel en stor
Dusk korsformede Pedicellarier, Fig. 2. Disse
Furepapil-ler have tildels Udseende af at staa i 3 Rækker, hvilket
hidrører derfra, at Adambulacralpladerne bære afvexlende
2 og 1 Papille. Nede i Furen, langs dens Sider, sees
enkelte temmelig smaa, langt fra hinanden staaende,
ligeformede Pedicellarier, der ere fæstede til Grunddelen af de
indre Ftirepapiller. Imellem den ydre Række Furepapiller
og den ventrale Række Randpigge er et smalt Belte, knapt
lmm bredt, paa hvilket Andes yderst faa, (2—3) temmelig
lange Pigge, men som forresten er nøgent.
De korsformede Pedicellarier ere ganske
overensstemmende med dem, der findes hos Asterias rubens, som ere
beskrevne og afbildede hos Ed. Perrier1; men da hans
Afbildning ikke er fuldkommen korrekt, henvises til vor
Afbildning, Fig. 5.
De ligeformede Pedicellarier, hvoraf der findes meget
faa og kun i Ambulacralfuren, ere derimod noget
forskjellige fra dem, der findes i overordentlig stor Mængde hos
Asterias rubens. Basaldelens undre Rand er meget krum.
Kjæverne ere temmelig korte, have en bred Grunddel, og
deres indre Rande, der ere besatte med Tænder, slutte tæt
sammen næsten lige ned til Basaldelen, saa at der findes
kun en meget liden Aabning længst nede imellem dem,
naar de ere lukkede, Fig. 6. For Sammenlignings Skyld
have vi afbildet en ligeformet Pedicellarie af Asterias
ru-bens, hvorved Forskjellen tydeligst sees, Fig. 14.
Ryghudens Skelet er bygget af større og mindre
Kalkplader, som ere flade paa den Side, der vender til
Krops-hulheden og hvælvede paa sin øvre Flade, hvor der findes
paa Midten en rund Forhøining, forsynet med en lille
Ar-ticulationsflade for en Pig, Fig. 7, a. Disse Kalkplader
have 3—4 Udløbere, Fig. 7, 6, der ere temmelig korte, og
som lægge sig taglagte paa de tilstødende Kalkpladers
Udløbere, hvorved fremkommer et Kalknet, hvis Masker ere
noget uregelmæssige og i Regelen ikke meget store, Fig. 7.
I enkelte, noget større Masker, sees 1—2 meget smaa
Kalkstykker at være indleirede.
Paa Siderne af Armene ere Kalkpladerne meget større,
have en Korsform, Fig. 7, c, og ere stillede i
regelmæssige Rækker, saaledes nemlig, at hver Arm af Korset
lægger sig paa en tilstødende Kalkplades Korsarm, hvorved
fremkommer aflange Masker, der ere stillede i 3
Længderader fra Armens Grund til dens Spids, Fig. 7, d. Af
disse Sideplader skulle vi lidt nærmere omtale de to
Rækker, der kunne betragtes som Randplader. De inderste, de
nærmest Bugfladen (ventrale Randplader), Fig. 2, a, ere
ikke ganske korsformede, forsaavidt som de mangle en Arm,
1 Ed. Perrier. Recherches sur les pédicellaires et les ambulacres.
Annales des Sc. Nat. 5 Serie, Tome XII pag. 228, pl. 17. fig. 2.
The ventral furrow is rather narrow, and is supplied
with two rows of long, flattened papillæ, of which those in
the interior row are the longest; their superior exterior
half as a large tuft of cruciform pedicellariæ (fig. 2).
Owing to the adambulacral plates carrying 2 and 1 papilla
alternately, the furrow-papillæ have somewhat the
appearance of standing in 3 rows. Within the furrow, along
its lateral surfaces, a few rather small rectiform
pedicellariæ are visible, placed at considerable intervals from each
other, and attached to the basal part of the internal
furrow-papillæ. Between the exterior row of furrow-papillæ, and
the ventro-marginal spines, there is a narrow, barely lmm
broad border, upon which extremely few, (2—3) tolerably
long spines are found, but which, is, otherwise, bare.
The cruciform pedicellariæ are exactly similar to those
found in Asterias rubens, described and illustrated by Ed.
Perrier,1 but, as his illustration is not quite correct, we
refer to our illustration (fig, 5).
The rectiform pedicellariæ; of which very few are
found, and situated only in the ambulacral furrow; are,
upon the other hand, somewhat different from those which
are found in such extraordinarily large numbers in Asterias
rubens. The inferior margin of the basal portion is much
curved. The jaws are rather short, and with a broad base;
their inner margins are furnished with teeth; and they close
together along the entire length of the jaws, almost up to
the base; so, that in the closed position, only a very small
opening between them is left at their base (fig. 6). For
the sake of comparison we have also illustrated a rectiform
pedicellariæ of Asterias rubens, by which the difference
is distinctly seen (Pl. Ill, fig. 14).
The dorsal dermal skeleton is constructed of larger
and smaller calcareous plates, flat on the surface facing
towards the body cavity, arched upon the superior surface,
where, there occurs a circular mesial prominence, furnished
with a small articulatory surface for a spine, (flg. 7, a).
These calcareous plates have 3—4 prolongations, (fig. 7, b),
which are pretty short, and placed so as to overlap with
the prolongations of the adjoining calcareous plates, by which
a calcareous reticulation is produced, composed of somewhat
irregularly formed meshes, which are, coiAmonly, not very
large (fig. 7). In a few of the larger meshes, 1 or 2 very
minute calcareous corpuscles are seen to be embedded.
On the lateral surfaces of the rays, the calcareous
plates are cruciform, and much larger (fig. 7, c) and they
are arranged in regular series, in such manner, that each
arm of the cross, overlaps an adjoining calcareous plate’s
cross-arm, producing thus, oblong meshes, distributed in 3
longitudinal rows extending from the origin of the ray,
to its distal extremity (fig. 7, d).
We shall speak a little more minutely at this point,
in regard to the two rows of lateral plates, which may be
considered to be marginal plates. The inmost, that is, those
1 Ed. Perrier. Recherches sur les pédicellaires et les ambulacres.
Annales des Sc. Nat. 5 Série, Tome XII pag. 228, pl. 17, fig. 2.
2*
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