Rinku, og som kun maa betragtes som forskjellige Udvik- 
lingsstadier. 
De af Théel særskilt beskrevne Geller, der findes paa 
de sphæriske eller ovale Legemer, og hvortil han tror at 
have fundet Nervegrene, ere 'efter vor Formening ikke andet 
end Epithelcellerne paa Peritoneum, der danner disse Le- 
gemers Oyertrek, hvor de ere temmelig spredte. 
I det hyaline Parti af Bindevævet, nærmest Epithel- 
laget, ere Hjulene leirede. De findes især paa Rygtladen, 
hvor de ligge temmelig tæt til hverandre, naar Dyret er: 
noget kontraheret; men spredes alt eftersom Kroppen ud- 
vider sig. Paa Bugfladen ere de yderst sparsomme og 
vanskelig at finde. Hjulenes Centraldel er paa den indre 
Flade forsynet med en rund Knop. Fig. 5; forresten ere 
de saa vel beskrevne af Dr. Théel, at vi kunne henvise 
dertil. De ligge flade i Huden, rage ikke over dennes 
Niveau, og ere ikke stilkede. 
Dr. Théel beskriver et eget Slags Geller, der ligge i 
Grupper, næsten som Drueklaser paa enkelte Steder i 
Huden. saavel hos M. brevis, som hos Trochoderma elegans; | 
ogsaa vi have seet lignende; men vi ere, tilbøielige til at 
antage dem for koagulerede Celler af Kropsvædsken, der 
tilfældigvis ere komne ind i Huden. Saadanne agglomere- 
rede Celler træffer man afsat snart paa Hudens indre 
Flade, snart paa Tarmen, snart paa Mesenterium og de 
Bindeveevstraade, der binder Tarmen til Huden, og ere 
stundom saa nøle fæstede til disse Dele, at man let kunde 
fristes til at antage dem for histologiske Elementer deraf. 
De tolv Tentakler ere fuldstændig lig dem hos M. 
Rinku, og som af os ere afbildede; kun have de nogle 
'Cirrer mere end Rink. 
Kalkringen, Fig. 6, a, er sammensat af 10 Stykker, 
der bærer 12 Spidser (Processer) paa den forreste Rand, 
saaledes nemlig, at ethvert af de to dorsale Radialstykker, 
der støde til det midterste dorsale Interradialstykke, er for- 
synet med to Processer, Fig. 6, 0, b, ligesom Spidsen paa 
de to midterste ventrale Radialstykker er den lengste, 
noget Sars har gjort opmærksom paa i hans Beskrivelse * 
over Oligotrochus vitreus. I det Hele taget ligner Kalk- 
ringen hos denne fuldstændig den hos M. brevis. 
Vandkarringen er som hos Synaptiderne i Alminde- 
lighed; den Poliske Blære er temmelig stor. ægformig, 
Ine, ©, @ 
Stenkanalen er meget kort, den har næsten S-Formen, 
er meget bred indad hyor den munder ud i Vandkarringen, 
Fig. 6, d, 7, d. Paa dens ydre Ende, der ved et stærkt 
Ligament, Fig. 7, a, er bundet til Hudens indre Flade. 
findes en bred Madreporplade, Fig: 7, b, der er ujævn paa 
Overfladen af de fremragende Kalkpigge, og hvori den 
Den norske Nordhavsexpedition. Danielssen og Koren: Holothurider. 
visceral cavity. They assume, exclusive of the two forms 
he has ‘figured, several others, bearing some resemblance 
to those of the spicules in Myr. Rinkii, and which must 
be regarded merely as representative of the divers stages 
of development. 
The cells on the spherical or ovate corpuscles, spe- 
cially described by Dr. Théel, and passing to which he 
believes to have detected nervous ramifications, are. 
our opinion, simply the epithelial cells of the peritoneum, 
in 
with which these corpuscles are invested when they occur 
comparatively dispersed. 
In the hyaline portion of the connective tissue, im- 
mediately beneath the epithelial layer, are embedded the 
wheel-shaped spicules. They occur in particular on the dorsal 
surface, where they crowd together on a slight contraction 
of the body, again dispersing when it expands. On the 
ventral surface they are very sparingly distributed. nay 
are difficult even to detect. The central portion of the 
spicules is furnished on the imner surface with a round 
knob, fig. 5; for the rest, they have been so excellently 
described by Dr. Théel as to render further notice super- 
fluous. They lie in a plane with the skin, never projecting 
above it, and are not pedunculate. 
Dr. Théel also describes a peculiar kind of ‘cells oc- 
curring both in M. brevis and Trochoderma elegans; they 
are arranged in groups, not unlike clusters of grapes, here - 
and there in the skin. We, too, have observed similar 
cells, but are melmed to regard them rather as cellular 
globules of coagulated perivisceral fluid that have chanced 
to find their way into the skin. Such agglomerate cells 
are met with on the inner surface of the skin, on the in- 
testine, on the mesentery, and on the membranous filaments 
that web the intestine to the skin; and they are so closely 
connected with those parts as to present every appearance 
of being histological elements. 
The twelve tentacula are exactly similar to those of 
M. kinkii, as figured by us, save in their having a few 
“more eirrhi. 
The calcareous ring, fig. 6, a, is composed of 10 seg- 
ments (ossicles) and has on the anterior margin 12 acuminate 
processes, arranged in such manner that each of the two dor- 
sal radial segments contiguous to the medial dorsal interradial 
segment is furnished with two processes, fig. 6,b,b, the pro- 
cess on each of the two medial ventral radial segments being 
the longest, a distinctive feature pointed out by Sars in 
his deseription of Oligotrochus vitreus. The general struc- 
ture of the caleareous ring in this species is the same as 
in M. brevis. 
The water-vascular ring as in other Synaptide; the 
Polan vesicle rather large, ovate. fig. 6, c. 
The sand-canal very short, in form closely resembling: 
the letter S; within, at the point where it opens into the 
water-vascular ring, exceedingly broad, fig. 6, d, 7. d. On 
its outer extremity, attached by a strong ligament, fig. 7, a, 
to the inner surface of the skin, occurs a broad madreporic 
body, fig. 7, b, and with this body, which the projecting 
9) 
