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68
kun hos ældre Individer ligge de tættere sammen og danne
næsten et sammenhængende Lag. hvorved de nærme sig
meget baade i Form og Anordning de, der findes hos Troch.
boreale, Fig. 19. Saavel de runde Kalklegemer som de
elliptiske bestaa af koncentriske Ringe og have en skjøn,
mørkvinrød Farve, kun enkeltvis ere de gule, Fig. 24De
ovale have i Midten ligesom en Kjerne, der altid viser sig
med en intensere Farve.
Den anden Form af Kalklegemerne ere farvefrie,
gjennembrudte Plader, fra hvis Midte reiser sig en
tre-armet Krone, der har en knopförmig fri Ende, forsynet
med 3 eller 4 runde Takker, Fig. 24, /. Det er denne
Ende og endel af Skaftet, som rager op igjennem de
om-’talte Papillers Aabning. Saavel Pladen som Skaftet er
beklædt af et tyndt Lag af Bindevæv, der danner ligesom
en Skede om Skaftet, hvilken er dækket af Epithelet og
Cutieula, Fig. 24, g. Disse Kalklegemer findes i stor
Mængde overalt paa Kroppen, men ere dog saavidt spredte,
at de ikke ligge tæt i hverandre, uden paa begge
Kropsenderne, Fig. 20. Her have de en mere langstrakt Form,
Fig. 19, og ligge saa tæt til hverandre, at de f. Ex. paa
den forlængede Haledel danne saagodtsom et Pantser.
Ogsaa disse Legemer have særdeles meget tilfælles med de
Kalkplader, der findes hos Troch. Thomsonii og boreale.
Den tredie Form af Kalklegemer er ganske
eiendommelig og minder om Tilværelsen af en Sgnapta, der
forlængst er forsvunden. Det er disse Legemer, der danne
den tidligere omtalte Stjerne, og som udgjør et Komplex
af 5—6 spatelformige Kalkstave, Fig. 24, h, og et
Kalkanker, Fig. 21. Dette stjerneformige Legeme er
indesluttet af en Hulhed, der dannes af Bindevævet, .og hvis
ydre Flade er beklædt af Epithelet, Fig. 24, i, i. Saavel
Bindevævet som Epithelet forlænger sig et Stykke op paa
Ankerstokken, men Kløerne ere nøgne.
Enhver spateldannet Kalkstav bestaar af et meget
langt og rundt Skaft, der som oftest er afrundet paa den
fri Ende, Fig. 21, a, og en bredere Del, eller Blad, der
er næsten rundt, temmelig tykt og forsynet med en stor
Mængde Huller, Fig. 21, b. Det er disse bredere Dele
med deres afrundede Rande, der støde til hverandre og
danne Stjernens Centrum, imedens Skafterne danne
Straalerne, Fig. 20, 21. Til Midten af Stjernens Centrum er
fæstet ved Bindevæv et bevægeligt Kalkanker, Fig.. 20, 21.
Ankerstokken er rund, meget lang, og den Del, der er
fæstet til Spatelbladene, har 5—6 listeformige
Fremstaaen-heder, alt eftersom Stjernen dannes af 5 eller 6 Stave, Fig.
21, c. Ankerets Kløer ere lange og tilspidsede, og paa
deres ydre konvexe Rand ere tre Takker, Fig. 21, d.
Ankeret kan bevæge sig til alle Sider ved sin ligamentøse
Sammenheftning.
type, which are the most numerous, generally occur
embedded in groups, fig. 24, e; in mature individuals only do
they exhibit a closer arrangement, constituting an almost
continuous layer, and hence approximating in form and
disposition those in Troch. boreale, fig. 19. Both the round
and the elliptic corpuscles consist of concentric rings, and
are of a vivid vinous red, a few only being yellow, fig. 24l.
The oval corpuscles have in the centre a kind of nucleus,
invariably of a deeper colour.
The corpuscles exhibiting the second form are
colourless perforate plates, from the centre of which springs a
three-armed corolla, having at its free extremity a knob,
furnished with 3 or 4 cylindric spines, fig. 24, /. It is
this extremity, together with part of the shaft, that
protends through the opening in the papillæ mentioned
above. Both the plate and the shaft are invested with a
thin layer of connective tissue, the shaft being, as it were,
invaginated in a sheath, covered by the epithelium and the
cuticle, fig. 24, g. These calcareous corpuscles occur
everywhere in large numbers on the body, but their arrangement,
saving at the extremities, is not so close as to bring them in
direct contact one with the other, fig. 20. Here (at both
extremities) they are more elongate in form, and so closely’
disposed, that in places, on the caudiform appendage for
instance, they constitute a kind of armature. These
corpuscles, too, have much in common with the calcareous
plates in Troch. Thomsonii and Troch. •boreale.
The third typical form in which these calcareous
corpuscles occur is eminently characteristic, indicating, it would
seem, a Sgtiapta stage of development, out of which the
animal has long since passed. It is these corpuscles that
form the stellate figure mentioned above; they, constitute,
too, a complex of spatulate calcareous rods, 5 or 6 in number,
fig. 24, h, as also a calcareous anchor, fig. 21. This
stellate figure£occurs in a depression, or cavity, in the
connective tissue, and has its outer surface clothed with the
epithelium, fig. 24, i, i. The connective tissue and the
epithelium are both prolonged some distance up on the
stock of the anchor; but the arms are naked.
The spatulate rods consist each of an exceedingly
long, cylindric shaft, rounded, as a rule, at the free
extremity, fig. 21, a. and of a bi*oader pinnate portion, almost
round, rather thick, and furnished with numerous apertures,
fig. 21, b. It is these broader parts with their rounded
margins that approximate to form the centre of the stellate
figure, the shafts representing the radii, figs. 20; 21.
Webbed to the centre of the stellate figure, is seen a moveable
calcareous anchor, figs. 20; 21. The stock of the anchor
is cylindric, exceedingly long, and the part webbed to the
spatulate lobes is furnished with linear apophyses, 5 or
6 in number, according as the stellate figure consists of 5
or of 6 calcareous rods, fig. 21, c. The arms of the anchor
are long and pointed, and their outer convex margin has
3 spines, fig. 21, d. The anchor is moveable in all
directions, by means of its ligamentous connexion with the
stellate figure.
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