‘et langt, rørformigt, gjennemsigtigt Legeme (det contrac- 
tile Kar), der gaar et Stykke bag paa Tarmen, hvor det 
ender i en kolbeformig Blindsæk, Fig. 27, g; 
det til Snabelens forreste Ende, hvor det deler 
danner Karringen, som følger Tentakelkraven i 
Bugtninger for at afgive Grene til Tentaklerne. 
sig, og 
alle dens 
Retractorerne ere 4, hvoraf de to Bugretractorer ere 
meget lange og tage 'deres Udspring med 3 Rødder fra den 
forreste Del af Kropshulhedens bagerste Trediedel, Fig. 
27, 1, imedens Rygretractorerne udspringe fra det forreste 
Parti af Kropshulhedens midterste Trediedel, Fig. 27, h. 
Strax bagenfor .Spiserørets forreste Ende forene de sig og 
danne ligesom en Skede om dette, idet de fæste sig som 
sædvanligt paa Mundskivens Rand. 
To Segmentalorganer, Fig. 27, 
omtrent 67” lange og 2mm brede ved deres Tilhæftnings- 
sted. Lidt bagenfor dette o& paa den Side, som vender 
imod Kropsvæggen, sees en liden oval, tragtformig Aabning, 
Fig. 28, a, der fører ind til Hulheden. 
Centralnervestrængen ligger langs Midten af Buefladen 
imellem begge Retractorerne og er temmelig tyk, Fig. 27, 
 k, 29, a. Den afgiver paa sit hele. Lab en Mengde Side- 
grene, der som oftest udgaa afvexlende og: tabe sig i Hu- 
den. Strax bagenfor Mundaabningen -deler den sig i to 
(Grene, Fig. 29, b, b, der slaa sig om 
y) te) 2 
hvor de tabe sig i et aflanet Ganglion 
der er ligesom indsnøret paa Midten. Fig. 29, c, 
op paa Rygsiden, 
(Hjerne), 
og som ligger imellem begge Rygretractorerne, just paa det 
Sted; hvor ‘disse forene sig. Saavel fra Svælgringen som 
fra Gangliet udgaa flere Grene, Fig. 29. 
'Centralnervestrængen 
“en Bindevævsskede, der danner det egentlige Neurilem. 
Paa hver Side af Nervestrængen iagttages et Muskel- 
baand, der er omtrent ligesaa bredt. som selve Nervestam- 
men; det strækker sig fra Svælgringen op til Nervestræn- 
gens bagerste Ende og er fast forenet til den udvendige 
Sideflade af Neurilemmet. Dette Muskelbaand bestaar af 
stærke Muskelfibre, hvoraf enkelte strække sig ud over den 
Del af Sidegrenene, der ligger frit i Kropshulheden, men 
forsvinde efterhaanden som Grenene gaa ind i Muskellagene 
eller tabe sig i Huden. 
. Théel: har iagttaget og beskrevet lignende Mu- 
Seton hos Phascolosoma Strombi. 
Intet Spor til Kjønsorganer har været at opdage. 
Farven. 
mørkere paa den forreste 
Snabelen noget lysere: 
Selve Kroppen olivengrøn, 
og bagerste Del. dens forreste 
1 Hjalmar Théel. Récherehes sur le Phascolion Strombi. 
Svenska Vetenskaps-Akademiens Handlingar, B. 24, No. 2. 
Kongl. 
fortil lober 
i, der ‘ere meget smaa, 
Svælget for at komme: 
og dens Grene ere omgivne af 
12 
retractors, 
spot where they ‘unite, 
to the 
the right, is seen a long, tubular, translucent body (the 
contractile vessel), protending a short distance back on the 
intestine, where it terminates in a cecum, cucurbit-like in 
form, fig. 27, g; anteriorly, it passes forwards to the extrem- 
ity of the proboscis, forming there the vascular ring, which 
accompanies the tentacular collar in all its windings, and 
sends off branches to the tentacles. 
Number of retractors 4; two of them, the ventral 
which are exceedingly long, take their origin, 
with 3 roots, on the anterior portion of the posterior third 
of the perivisceral cavity, fig. 27, 1, whereas the dorsal 
retractors originate on the anterior portion of the medial 
third of the perivisceral cavity, fig. “27, h. Immediately 
posterior to the anterior extremity of the esophagus, the 4 
retractors unite, and form, as it were, a sheath for that or- 
as usual attached to the margin of the oral disk. 
Two segmental. organs, fig. 27, 7, exceedingly small, 
about 6””" long and 2”” broad at the point of attachement. 
A little posterior to the latter, and on the side facing the 
wall of the body. occurs a small, ovate, funnel-shaped aper- 
ture, fig: 28, a, leading down into, the cavity. 
The central nervous chord, which is comparatively 
thick, extends along the middle of the ventral surface, be- » 
gan, being 
tween the two ventral retractors, figs. 27, k; 29, a. 
Throughout its entire course it sends off numerous sub- 
sidiary branches, which, as a rule, issue alternately, and 
coalesce with the skin. Immediately posterior to the buc- 
divides into two. branches, fig. 29, 0, b, 
which, winding round the gullet, reach up to the dorsal 
surface, and are there lost in an oval- shaped ganglion 
(brain), — constricted, as it were, in the middle, fig: 29, c, 
— lying between the two dorsal retractors, in the exact 
Both from the pharyngeal ring 
and from the ganglion, proceed several branches, fig. 29. 
The central nervous chord and its branches are in- 
vaginated in a sheath of connective tissue, which constitutes 
the true neurilem. 
cal aperture, it 
On either side of the nervous chord is observed a 
muscular band, about equal in. breadth to the nervous 
trunk itself, extending from the pharyngeal ring to the 
posterior extremity .of the nervous chord, and firmly affixed 
exterior lateral surface of the neurilem. These 
muscular bands consist of strong muscular fibres, some of 
which protend beyond the portion of the subsidiary branches 
lying free in the perivisceral cavity, but are gradually lost, 
as the branches pass into the muscular layers, or coalesce> 
with the skin. å | 
Dr. Théel! has observed and deseribed similar muscu- 
lar bands in Phascolosoma Stromibi. 
Of generative organs no trace could be detected, 
Colour. 
Trunk olive-green, both extremities of a darker shade. 
Proboseis somewhat lighter; its anterior extremity, for 
' Hjalmar Théel. Récherches sur, 
Svenska .Vetenskaps-Akademiens Handlingar, B. 
le Phascolion Strombz. 
ZAIN OR 
Kongl. 
