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Vandkarringen danner en temmelig smal Kanal, der
ligger strax bagenfor Kalkringen, og omgiver det indknebne
Spiserør lidt foran det Sted, hvor dette gaar over i Maven,
Fig. 3, k. Fra Ringkanalen udgaa 5 Kanaler, 3 paa
Bugsiden og 2 paa Ryggen. De to af Bugkanalerne, der
udløbe fra Siderne, dele sig hver i 3 Grene, hvoraf den
største, der kan betragtes som Kanalens Fortsættelse, gaar
til Siden, løber langs den indre Flade af Kropsvæggen
ligetil den bagerste Ende og danner Længdekarret, hvoraf der
altsaa er to, et paa hver Side af Bugen. De to andre
Grene gaa til hver sin Tentakel, hvori de udbrede sig.
Den tredie Bugkanal, ligesom Rygkanalerne afgive hver 2
Grene, en til hver sin Tentakel. Fra Længdekanalernes
ydre Væg udgaar en Gren til hver Fod, og uden at kunne
angive det med fuld Sikkerhed, forekom det os, som om
der paa den indre Væg, især paa den bagerste Del af
Længdekarret, fandtes Udbugtninger, der laa nedsænkede i
Huden og kunne svare til Fodampullerne hos mange
Holo-thurider, Noget som virkelig finder Sted hos Elpidia ifølge
Dr. Théels Angivelser. Længdekanalerne ere ligesaa tykke
som selve Vandkarringen, og deres indre Flade er cilierende
ligesom dennes.
Den Poliske Blære er pæreformig, meget stor med
en temmelig kort Stilk, der gaar som sædvanlig over i
Vandkarringen paa Bugsiden, Fig. 3. 1.
Stenkanalen er temmelig lang, smal og slangeformig;
dens yderste Ende er afrundet og fastvoxet til Huden ved
den ydre Rand af den venstre Rygmuskel, just paa det
Sted, hvor Mundskiven gaar over i Kroppen. Strax
indenfor den fastvoxede Ende sidder Madreporpladen, der danner
en knopformig Forhøining paa Stenkanalen.
Madreporpladen har en meneandrisk Overflade med Forhøininger og
Fordybninger, og hvis Organisation ikke synes at afvige
væsentlig fra Madreporpladen hos Trochostoma1. Fra
Madreporpladen bugter Stenkanalen sig henimod
Vandkarringen, hvor den udmunder paa Rygsiden ligeoverfor den
Poliske Blæres Udmunding. Stenkanalen bestaar af et
temmelig fast Bindevæv ; men er uden Kalk.
Blodkarsystemet frembyder intet Særegent. Tarmens
Rygkar begynder i den Forsnevring, som findes der, hvor
Maven gaar over i Tarmen; det følger nu dennes
Slyngninger lige ned til Rectum. Paa denne Vei afgiver det en
Mængde Sidegrene til Tarmen, hvilke anastomosere med
Bugkarrets Forgreninger, og danne derved Netudbredninger
i Tarmenes Vægge. Desforuden afgiver det Grene til
Me-senteriet og en temmelig stor Gren til Kjønsorganerne.
1 Se Magazin for Naturvid. 24 Bind. Christiania 1878.
Immediately posterior to the calcareous ring, a rather
narrow canal, forming the water-vascular ring, encircles the
constricted oesophagus, a little in advance of the point where
the latter opens into the stomach, fig. 3, k. From the
annular canal branch off 5 canaliculated ramifications, 3
on the ventral and 2 on the dorsal surface. Two of the
ventral canals, which issue from the sides, divide each into
3 branches, the largest of which may be regarded as the
continuation of the annular canal; it takes a lateral
direction, running along the inner surface of the wall of the
body straight to the posterior extremity, and forms the
longitudinal vessels, which accordingly are two in number,
one on either side of the belly. The two other branches
proceed each to a tentacle, in which they ramify. The
third ventral canal and the two dorsal canals divide each
into 2 branches, proceeding to as many tentacles. From
the outer wall of the longitudinal canals a branch proceeds
to every sucker; and it seemed to us, though we cannot give
it as a fully determined character, that on the inner wall,
and more especially on the posterior portion of the
longitudinal vessel, were sinuous processes, embedded in the
skin, analogus to the pedal ampullæ in many Holothurians,
and which, according to Dr. Théel, do actually occur in
Elpidia. The longitudinal canals are equal in thickness to
•the water-vascular ring itself, and their inner surface
is, in common with that of the latter, furnished with
vibratile cilia.
The Polian vesicle is pyriform, very large, and has
a rather short stem, prolonged, as in other Holothurians,
into the water-vascular ring on the ventral surface, fig. 3,1.
The sand-canal is rather long, narrow, and flexuous,
its upper extremity being rounded, and connate with the
skin at the outer margin of the left dorsal muscle, exactly
where the oral disk passes into the body. Immediately
beneath the connate extremity occurs the madreporic body,
as a globular protuberance on the sand-canal. The
madreporic plate has a meneandrian surface, exhibiting a succession
of eminences and depressions; its structure does not appear
to be essentially different from that of the madreporic plate
in Trochostoma.1 From the madreporic plate, the
sand-canal winds on to the water-vascular ring, where it
disembogues on the dorsal surface opposite to the outlet of the
Polian vesicle. The sand-canal consists of rather firm
connective tissue, but exhibits no traces of calcareous deposit.
The circulatory system is not distinguished by any
peculiar feature. The dorsal vessel of the intestine has its
origin in the constricted passage through which the stomach
opens into the intestine, accompanying the convolutions of
the latter down to the rectum. On its course it sends off
numerous lateral branches to the intestine, which
anastomose with the ramifications of the ventral vessel, forming
reticulated vascular assemblages on the intestinal walls.
Branches also proceed to the mesentery, and one rather
large ramification strikes off to the generative organs.
1 Vidt Magazin for Naturvid. 24 Bind. Christiania 1878.
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