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Leddeflader for Tangen, Fig. 7, a. 8, a. Kjæverne ere
langstrakte, brede forneden, ende foroven i en Spids og ere
forsynede med fine Tænder langs deres indre Rande, Fig.
7, b. 8, b.
Pedicellarierne, der omgive Piggene paa de to distinkte
Rækker udenfor Furepiggene, ere alle korsformige
(Pédi-cellaires croisés), stilkede og adskille sig ikke væsentlig fra
denne Form hos Asterider med 4 Rader Fødder, Fig. 6.
Paa Armenes Ryg og tildels paa Siderne findes
overalt ved Piggenes Grund dels enkeltvis, dels smaa Hobe af
korsformede Pedicellarier; men foruden disse træffes ogsaa
her en tredie Form, der vel er lige, men ganske
forskjellig fra dem, som sees langs Ambulacralfuren.
Denne tredie Form Pedicellarier, der ere meget
sparsomme og altid isolerede, have en Lyreform, Fig. 9.
Basaldelen er halvrund, indtager en Trediedel af Pedicellariens
Længde, har paa den øverste, næsten lige Rand en lidt
afrundet Midtdel, Fig. 9, a. 10, a. Kjæverne ere meget brede
med indskaarne Sider og paa deres øverste Halvdel ere de
indvendig forsynede med 3—4 Tverrækker fine Tænder,
imedens den hele ydre Flade har 5 Længderækker Vacuoler.
Siderandene ere glatte, men den øverste, afrundede Rand
«ynes at være tandet, Fig. 9, b. 10, b.
Hudskelettet dannes af større og mindre, langstrakte,
rundagtige Kalkstykker, der, idet de føie sig sammen, danne
et uregelmæssigt, stærkt Bjelkenet med store Masker, hvori
sees Tentakelporer, Fig. 4. 5. Disse Kalkbjelker bære en
•eller flere Pigge, alt efter deres Størrelse.
Naar Søstjernen er tørret, rage Kalkstykkerne op over
Huden og danne Kamme, der gaa mere eller mindre
paa-tvers af Armen, Fig. 2.
Henimod Ambulacralfuren antage Kalkstykkerne baade
en mere regelmæssig Form og Anordning. De danne her
to distinkte Længderækker og ligge taglagte paa hverandre,
Fig. 11. Kalkstykkerne i den indre Række ere temmelig
flade, triangulære, Fig. 11, a, og støde med sin indre, brede
Rand umiddelbart til to Ambulacral- og Adambulacralplader,
Fig. 11, b, c. Paa deres ydre Flade bære de to Pigge,
der staa efter hinanden og hjælpe til at danne den første
Række Pigge udenfor Furepiggene. Disse Kalkstykker kunne
betragtes som ventrale Randplader.
Kalkstykkerne i den ydre Række er næsten T-formige,
Fig. 11, d, og støde med den brede Del til de ventrale
Randplader, hvoraf de for en liden Del dækkes, Fig. 11, a,
imedens den smalere Ende støder til de almindelige,
langstrakte Kalkbjelker, Fig. 11, e, der danne Hudskelettet.
Paa deres ydre Flade bære de to Pigge, der staa ved Siden
af hinanden og hjælpe til at danne den «anden Række Pigge
udenfor Furepiggene. Disse T-formige Kalkstykker kunne
betragtes som dorsale Randplader.
Adambulacralpladerne ere temmelig smaa, fladtrykte,
erance occurs. The sides furnish articulator}’ surfaces
(figs. 7, a. 8, a). The jaws are long, broad at the base,
and terminate anteriorly in a point; they are, along the
inner edge, furnished with minute teeth (figs. 7, b. 8, b).
The pedicellariæ which environ the spines of the two
distinct series found outside of the furrow-spines, are all
cruciform pedicellariæ, (Pédicellaires croisés) and are seated
on peduncules. They do not essentially differ from those
pertaining to Asteridæ having 4 rows of suckers (fig. 6).
On the abactinal surface of the rays, and, partly, also
on their lateral surfaces, cruciform pedicellariæ are every
where visible; appearing at the base of the spines, partly
singly, and, partly, in small clusters. Besides these, there
is also found a third form of pedicellariæ, which although
apparently rectiform, is yet quite different from those visible
along the ambulacral furrow.
This third form of pedicellariæ is lyrate, occurs much
less frequently, and is always isolated (fig. 9). The basal
part is semicircular and extends over a third part of the
whole length; on the superior nearly straight margin there
is a slightly rounded medial part (figs. 9, a. 10, a). The
jaws are very broad, with hollowed sides, and their superior
halves are supplied on the interior, with 3—4 transverse
series of minute teeth, whilst the entire exterior surface
has 5 longitudinal series of vacuola. The lateral margins
are smooth, but the superior, rounded margin, appears to
be denticulate (figs. 9, b. 10, b).
The dermal skeleton is formed of smaller, and larger,
elongate, rounded calcareous ossicles, which, by abutting on
each other, form an irregular, strong, reticulation, with large
meshes in which tentacular pores are visible (figs. 4, 5).
These ossicles carry one or more spines according to their
size.
When the starfish is dried, the calcareous ossicles
project beyond the integument, forming ridges, which extend
across the rays, in a more or less transverse direction.
Towards the ambulacral furrow, the calcareous ossicles
become more regular, both in form and arrangement. In
this situation, they form two distinct, imbricate, longitudinal
rows (fig. 11). The calcareous ossicles of the inner row
are triangular and somewhat flat (fig. 11, a). Their broad
inner margin abuts upon two ambulacral and adambulacral
plates (figs. 11, b, c). On the outer surface they carry
two spines, one situated behind the other, and these assist
in forming the first furrow-series. These calcareous ossicles
may be considered to be ventro-marginal plates.
The calcareous ossicles of the outer row, approach
in form to the letter T, (fig. 11, d), and their broad part
abuts on the ventro-marginal plates, and is partly covered
by these (fig. 11, a), whilst, the narrow extremity abuts on
the ordinary elongate rods, which form the dermal skeleton
(fig, 11, e). On their external surfaces they carry two
spines, placed side by side, which assist to form the
furrow-series. These tee-formed calcareous ossicles may be
considered to be dorso-marginal plates.
The Adambulacral plates are rather small, flattened,
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