sidste nedstigende Slynge, uden at være bunden til den, og 
- hverken den ene eller den anden staar i nogen Forbindelse 
med Karsystemet. 
Det har været almindelig antaget, at disse forgrenede 
Rør tjene som Respirationsorganer, idet de skulle optage 
Sovandet fra Kloaken, og efter at have afgivet det fornødne 
Surstof til Blodet, skulde det igjen udstødes, tilsat med en 
Del af de for Blodet ubrugelige Stoffe. 
Hos en hel Del Holothurider foregaar ogsaa en rhyt- 
misk Udvidning og Sammentrekning af Kloakaabningen, 
hvorved Søvandet inddrages og udstødes; men om dette 
jages op igjennem Rørene og fylder de mangfoldige Blærer, 
der da skulde sammentrække sig for atter at støde Vandet - 
ud, eller med andre Ord, :om der virkelig 1 de nævnte Rør 
og Blerer foregaar en Diastole og Systole, saaledes som 
Tilfældet er med Lunger i Almindelighed, det tør være 
-Tyivl underkastet. En saadan Tvivl har ogsaa til forskjel- 
lige Tider været reist; saaledes er Johannes Miller den 
første, der har ytret den Formening, at disse saakaldte 
Lunger neppe staa i Respirationens Tjeneste, da det fore- 
kom ham besynderligt, at kun den ene Stamme havde 
Blodkar, imedens den anden var uden Blodkarforbindelse 
med Tarmen. Han er tilboielig til at antage dem for 
Appendices til Fordøielseskanalen, og sammenligner dem 
med Analblinderørene hos Asteriderne. 
Gegenbauer! deler vistnok den samme Mening og 
henfører dem til Tarmkanalens Tilhængsorganer, idet han 
ytrer: “Omendskjondt disse saakaldte Lunger — indre 
Aandedrætsorganer — med Hensyn til deres Funktion ere 
forskjellige fra de interradiale Blindrør paa Søstjernetarmen, 
saa komme de dog disse nær 1 morphologisk Henseende og 
synes at være en videre Udvikling af de hos Asteriderne 
forekommende meget simple Ror’. Men hverken Johannes 
Miller eller Gegenbauer har, saa forekommer det os, kunnet 
levere noget fuldgyldigt Bevis, støttet paa rene lagttagelser, 
for deres Mening, hvorfor de ogsaa opfordre Forskere til 
at skjænke disse Organer deres fulde Opmærksomhed. 
Vi have paavist, at hos Trochostoma, hvor disse an- 
tagne Lungeapparater ere meget udviklede, udspringe de 
fra selve Tarmen uden nogen Karforbmdelse med denne. 
Heldigvis have vi havt flere Exemplarer i forskjellige Ud- 
viklingsstadier at raade over, saa at Observationerne derved 
have vundet i Sikkerhed. 
Hos et 10”” langt Individ, hvor intet Spor saaes til 
Generationsorganerne, fandt vi Rørene ikke meget udvik- 
lede; det høire dannede ved sit brede Udspring en tragt- 
formig Forlængelse af Tarmvæggen, hvilken indtog omtrent 
en Trediedel af Dyrets Længde, og var aldeles opfyldt af 
det samme lerede Indhold, som den fuldproppede Tarm, 
Tab. VII, Fig. 11, a. Ved den øverste spidse Ende af 
Tragten blev Røret tyndt og næsten vandklart; men snart 
1 Gegenbauer. Grundriss der vergleichenden Anatomie. 2te 
Aufl. 1878, pag. 228. 
52 
“is a question which has been frequently raised. 
tube, or tree, is placed close to the last descending convo- 
lution of the intestine. without however being webbed to it, 
and neither' the one nor the other have any connexion what- 
ever with the vascular system. 
These ramose tubes have generally been regarded as 
performing the office of respiratory organs, the water being 
sucked up through them from the cloacum, and then, after 
it has given off the necessary amount of oxygen to the 
blood, ejected, with some admixture of substances eliminated 
from the blood. i 
In many Holothurians there is a rhythmic expansion 
and contraction of the cloacal ‘opening, whereby the 
water is sucked in and ejected; but whether it be forced 
up through the tubes and fill the numerous vesicles, which 
in that case would, as in other respiratory organs, contract 
and expand with a regular alternate stroke — systole, dia- 
stole — to expel the aquiferous fluid, is doubtful. Indeed this 
Johannes 
Miiller was the first to state that, in his opinion, these 
“lungs” could hardly perform the office of respiration; it 
struck him as strange, that one only of the respiratory 
tubes should be furnished with blood-vessels and the other 
have no circulatory connexion whatever with the intestine. 
He would regard them rather as appendices to the digestive 
canal, and compares them to the cæca-like anal tubes in 
the Asteridæ. 
Gegenbauer? shares this view, regarding them as mere 
appendages of the intestinal canal. He expresses himself 
as follows: — “These ‘lungs,’ as they are termed — inter- 
nal respiratory organs — do indeed, as to their function, 
differ from the eæca-like interradial tubes in starfishes, but 
morphologically they bear considerable resemblance to those 
organs, and would seem to be a further development of 
the very simple tubes in the Asteridæ.” But neither Miller 
nor Gegenbauer have, we think, furnished satisfactory proof, 
from autoptical observations, of the soundness of their hypo- 
thesis; imdeed, they both call on naturalists to give these or- 
gans a full share of attention. 
Now, we have shown that this respiratory apparatus 
originates in Trochostoma, which has it highly developed, 
on the intestine itself, without however haying any vascu- 
lar connexion with that organ. Fortunately, we have had 
before us several specimens, representing different stages of 
growth, which has given a more conclusive character to 
our results. 
An example, 10”” in length, in which no trace 
of generative organs could be detected, had the tubes but 
slightly developed; the right tube formed at its origin 
a funnel-shaped continuation of the intestinal wall, occu- 
pying nearly a third of the length of the animal, and was 
stuffed full of the same clayey substance that distended 
the intestine, Pl VII, fig. 11, a At the superior 
acuminate extremity of the funnel, the tube became thin 
2te 
' Gegenbauer. Grundriss der vergleichenden Anatomie. 
Aufl, 1878, pag. 228. 
