. 66 
tykt paa Midten, havde en eylindrisk Figur med en tvers 
-afskaaren Forende, imedens den bagerste Ende havde, som 
sædvanligt, en haleformig Forlængelse med 5 Tender om- 
kring Kloakaabningen, hvilken Forlængelse ikke afviger 1 
Form eller Størrelse fra den, der er angivet hos Troch. 
Thomsonii og boreale, Fig. 1. 
Paa den forreste Ende findes Mundskiven, der vender 
lidt mod Bugfladen, og 1 hvis Centrum sees den runde, lidt 
foldede Mundaabning. Omkring denne har Mundskiven en 
glat, lidt hvælvet Del, Fig. 1, a, 2, a, og i Skivens Rand 
ere 15 cylindriske, indtil 6”” lange Tentakler, der paa den 
bredere Del (Bladet) er forsynet med 5—7 Papiller, hvoraf 
den midterste altid er den tykkeste og største, Fig. 1. 3,.a. 
:Paa smaa Exemplarer er der kun 3 Papiller. Naar Ten- 
taklerne ere noget indtrukne (de kunne forresten ganske | 
trækkes ind i sig selv), fremkommer Hjulformen, idet Ten- 
taklerne da ligge i aflange Gruber, som adskilles -ved rør- 
formige, mørk brunfarvede Forlængelser af Kroppens for- 
reste Rand, hvilke Forlængelser gaa hen til den glatte 
hvælvede Del af Mundskiven, Fig. 2 (se vor Beskrivelse af 
Trochostoma Thomson). 
| Tversnit af Huden viser ingen Forandring i anatomisk- 
histologisk Henseende fra de to foregaaende Arter, hvor- 
imod Afvigelser finde Sted med Hensyn til Kalklegemerne, 
Tab. X, Fig. 6. Der findes nemlig kun en Hovedform, 
gjennembrudte Kalkplader med Kroner. Disse Kalkplader 
variere noget efter det Sted af Kroppen, paa hvilket de 
ere leirede, men alle have de den trearmede Grundtype. 
Meget hyppigt er Skaftet (Kronen) delt lige fra Roden, og 
da ser det ud, som om der var to Kroner paa hver Plade, 
Tab, DX, Bie 6 
I levende Live er Farven graagrøn, spillende i det 
violette. Tentaklerne ere temmelig klare med et let violet 
Anstrøg, der især er tydeligt paa Papillerne. Den forreste 
Halvdel af Kroppen bevæger sig op og ned og strækker 
sig ofte ud med sine Tentakler for at søge Føde, ligesom 
Haledelen bevægede sig i alle Retninger. Den bredere Del 
af Kroppen forholdt sig temmelig rolig. Analaabningen 
udvidede sig kun sjelden. Den haleformige Forlængelse 
kunde indtrækkes temmelig betydeligt, og blev derved for- 
kortet, uden dog at forsvinde. 
At ogsaa denne Art maa 
henføres til vor opstillede Slægt Trochostoma, kan vel ikke 
drages 1 Tyivl. | 
Findested. 
Station 260. Porsangerfjord. Stat. 261. Stat. 323. 
In small examples there are only 3 
‘comparatively quiescent. 
the middle 30””, was cylindric in form, with the anterior 
extremity truncate; the posterior extremity, as is commonly 
the case in this genus, had a caudiform appendage, fur- 
nished with 5 teeth, or dentelli, round the anal opening, 
the said appendage differing in no wise as regards form or 
size from that in Troch. Thomsoni and Troch. boreale,: fig. 1. 
On the anterior extremity is seen the oral disk, 
slightly inclining towards the ventral surface, and in its 
centre the circular and slightly folded buccal aperture. 
Round the latter, the oral disk exhibits a smooth and 
slightly arcuate surface, figs. 1, a; 2,a; and, extending along 
the margin of the disk, are seen 15 cylindric tentacles, the. 
longest measuring 6””, which on the broader part (the 
pinna, or leaf) have from 5 to 7 papille, that in the 
middle being invariably thickest and largest, figs. 1; 3, a. 
3 papille. On the ani- 
mal drawing in its tentacles a little: (these organs are . 
wholly retractile), the rotate form makes its appearance, 
the tentacles then occupying oblong cavities, which are 
separated one from the other by tubular continuations — * 
dark-brown in colour — of the anterior margin of the 
body, the said continuations proceeding to the smooth, ar- 
cuate portion of the oral disk, fig. 2 (see our description . 
of Trochöstoma Thomsonii). 
A transverse section of the skin exhibits no histologi- 
cal deviation from the two preceding species; but as regards 
the calcareous corpuscles, various distinctive features are 
apparent, Pl. X. tig. 6. For mstance, they are all com-, 
prised in one fundamental form, viz. perforate calcareous 
plates with corollæ. These calcareous plates vary some- 
what, according to the part of the body. where they lie 
embedded; but the trifid, three-armed type is common to 
all. Very frequently the shaft (corolla) is cleft to the 
base, and in that case two corollæ appear to spring from 
each plate,. Pl. IX, fig. 5. 
When alive, the animal is of a grey-green colour, 
bordering on violet. The tentacles are comparatively bright, 
with a tinge of violet, on the papillæ in particular plainly 
perceptible. The anterior half of the body moves up and 
down, and is frequently stretched out, with the tentacles exsert- 
ed, in search of food; the caudiform appendage kept moving, 
too, in all directions; the broader portion of the body remained 
The anal opening was but seldom 
expanded. The cauditorm appendage admits of being con- 
siderably retracted; but though often very much shortened, 
it was never seen wholly to disappear. The propriety of 
referring also this species to our new genus Trochostoma, 
will not, we opine, be called in question. | 
Locality. 
Station 260; the Porsangerfjord: Stations 261 and 323. 
