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18
Exemplarer, ere Undersøgelserne i enkelte Dele blevne
mindre udtømmende, end Tilfældet havde været under
gunstigere Omstændigheder. Vore Observationer kunne
forhaabentlig i nogen Grad raade Bod herpaa.
I det indre Bindevævslag hos Elpidia have vi fundet
lignende elliptiske, skivedannede Kalklegemer, som de vi
have beskrevet og afbildet hos Irpa. Hvad Muskulaturen
betræffer, saa ere de saakaldte Ringmuskler paa den forreste
og bagerste Del af Kroppen virkelig cirkulære, som af
Théel bemærket, men paa den midterste Del gaa de ikke
rundt, men ophøre enten ved Randen af Længdemusklerne
• eller et ganske lidet Stykke indenfor Randen, henimod
Midten.
Vandkarsystemet hos Elpidia er ifølge vore Iagttagelser
temmelig overensstemmende med det hos Kolga og Irpa.
Fra Vandkarringen udgaa 5 temmelig korte Hovedstammer,
hvoraf de to, der tilhører Biviet, dele sig hver i 2 Grene,
der gaa til hver sin Tentakel, de to Sidestammer dele sig
hver i 3 Grene, af hvilke den ene, som er den største,
danner Længdekanalen, medens de to andre gaa til hver
sin Tentakel; de 5 Hovedstammer dele sig altsaa i 12
Grene.
Dr. Théel har kun iagttaget 2 Sidekanaler, der efter
ham udgik fra Vandkarringen; men han gjør udtrykkelig
opmærksom paa, at han paa Grund af Undersøgelsernes
Vanskelighed ikke har havt tilstrækkeligt Materiale for at
komme til fuld Sikkerhed. Hvad der især tiltrak sig vor
Opmærksomhed med Hensyn til Vandkarsystemet hos
Elpidia, var de af Théel beskrevne Skillevægge (Klapper) i
Længdekarrene (se Mémoire sur VElpidia par H. .T. Théel,’
Tab. 5, Fig. 28, 29, C, C), og det saameget mere, som
han ikke har fundet nogen Kontinuitet i Cirkulationen, idet
de antagne Skillevægge ikke vare forsynede med nogen
Aabning, men vare i hele Circumferentsen fastvoxede til
Karrets indre Væg, saa at der skulde være et særeget afsluttet
Rum imellem 2 Skillevægge, og fra dette Rum skulde
Karret udbugte sig og danne Fodampullen.
Den ovenciterede Afbildning, som ledsager
Beskrivelsen, er i det Væsentligste aldeles korrekt; men da Dr.
Théel ikke har iagttaget nogen Kontinuitet i Længdekarrets
Lumen, — er hans Opfatning bleven ganske forskjellig fra
den, vore Undersøgelser have ledet os til. Nogen
fuldstændig Injektion af Længdekarret er det ikke lykkedes os
at foretage; derimod have vi kunnet drive de i
Injektions-vædsken indeholdte Luftblærer igjennem Karrets hele
Længde, hvorved vi have overbevist os om, at
Længdekanalen ikke er afbrudt ved Skillevægge; men at
Vand-vædsken uhindret cirkulerer hos Elpidia ligesom hos andre
Holothurider
limited, and hence his results are less comprehensive than
would otherwise have been the case. Our observations will,
we hope, serve to complete his description.
In Elpidia we have detected in the inner layer of
connective tissue elliptic, discoid calcareous corpuscles
similar to those occurring in Irpa, which are described and
figured in our paper on that genus. With regard to the
muscular development, the so-called annular muscles on the
anterior and posterior portions of the trunk did indeed
prove to be strictly circular, as noticed by Dr. Théel, but
in the medial region their form is not that "of a perfect ring,
since they terminate at the margin of the longitudinal
muscles or almost immediately within it, never meeting in the
middle.
The aquiferous system in Elpidia, according to our
observations, presents a close resemblance to that in Kolga
and Irpa. From the vascular ring protend 5 principal stems,
comparatively short; 2 of these, belonging to the bivium
divide dichotomously, each of the branches proceeding to a
tentacle; the two lateral stems divide trichotomously, one
of the branches — the largest — forming the longitudinal
canal; the remaining two [proceed each to a tentacle. The
5 principal stems divide therefore into 12 branches.
I)r. Thcel has not observed more than 2 lateral
canals, which, according to his diagnosis, issue from the
water-vascular ring; but he lays particular emphasis on the
fact, that with so complex a structure the materials
before him were insufficient to arrive at absolute certainty.
A characteristic peculiarity connected with the aquiferous
system in Elpidia that attracted our special notice, was the
valvular septa in the longitudinal vessels, minutely described
by Dr. Théel (vide Mémoire sur VElpidia, par H. .1. Théel.
Pl. 5, figs. 28, 29, C, C), particularly since that naturalist
has failed to detect any continuity in the circulation, the
supposed septa not being furnished with an aperture, but
having their whole circumference connate with the inner
wall of the vessel; hence two septa would enclose a
separate space; and from this space the vessel is said to bulge
out, forming the pedal ampulla.
The figure accompanying the description referred to
above, agrees in the main with what we have ourselves
observed, but Dr. Théel not having detected any continuity
in the lumen of the longitudinal vessel, he naturally
entertains on this point quite a different view to that which we
have been led to adopt. A complete injection through the
longitudinal canal we have failed to effect, whereas the bubbles
of air contained in the fluid injected were repeatedly forced
down the entire length of the vessel, affording to us
satisfactory proof that the longitudinal canal is not interrupted
in its course by septa, but that the aquiferous fluid
circulates freely in Elpidia, as in other Holothurians.1
1 Herover have vi nærmere udtalt os i en Afhandling optaget i
"Magazin for Naturvidenskaberne," 25 Bind, pag. 101.
1 We have treated this subject more at large in a Memoir
which appeared in "Magazin for Naturvidenskaberne," 2*1 Bind, pag. 101.
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