Huden. forskjellig formet, 
ingen Anledning til at kunne iagttage Hjulformen. 
Trochostoma Thomsonii lever paa Lerbund. og den 
fører visselig et meget stille Liv; nogen synderlig Bevægelse 
kan den ikke udfore; idetmindste kan den ligge ganske 
ubevægelig i Observationskarret i mange Dage, og man 
skulde tro, at der intet Liv længere var tilstede, dersom 
man ikke af og til saa en Excrementprop komme ud af* 
Analaabningen, og at de oftere nævnte rørformige Forlæn- 
gelser paa Mundskiven forandrede noget Form. Det .er 
imidlertid rimeligt, at den ikke vedbliver at leve paa samme 
Sted hele Livet igjennem, men at den kan føres ved Strøm- 
ninger fra det ene Sted til det andet; thi meget let kommer 
den i en rullende Bevægelse. 
Farven er violet, snart lys, snart mørk, spillende 
noget i det Brunlige mod Bugfladen. Længdemusklerne ere 
skidden gule. Mundskivens rørformige Forlængelser, lige- 
som den forreste Del af Kroppen er i Almindelighed bleg- 
violet. Mundskivens glatte Del og Tentaklerne ere hvid- 
gule. Den haleformige Forlængelse bleg gul-violet. Paa 
et Par Exemplarer var Farven mere grønlig med større og 
mindre mørkebrune, næsten sorte Flækker; den haleformige 
Forlængelse hvid med et blegt rosenrødt Skjær, og hele 
Mundskiven næsten hvid, naar undtages de rørformige For- 
længelser, der vare bleg groniige. 
Findested. 
‘Station 18, Station 33, Station 137. 
Slægtskarakter. 
Legemet langt, cylindrisk. Den forreste Ende tvert- 
afskaaren. Mundskiven. forsynet med 15 rørformige For- 
længelser, afvexlende med 15 aflange Fordybninger, hvori 
findes 15 papilformige Tentakler. Den bagerste Ende hale- 
formig forlænget. Analaabningen omgivet af 5 Tænder. Huden 
meget ru. Ingen Fødder. To Tarmappendices (Lungetræer). 
Artskarakter. 
Tentaklerne mudlmeuisne forsynet med 3 smaa Papil- 
ler, hvoraf den midterste er den største. eee 1 
dels ovale, dels elliptiske, dels 
større gjennembrudte Plader med Kroner, og hvori Grund- 
formen er‘trearmet. Hudens Farve er violet, noget brunlig 
mod Bugfladen og lysere i Bag- og Forenden. 
e 
the rotate part, which are seen more or less to swelk It 
frequently happens, however, that a small portion only of * 
the oral disk makes its appearance, in which case the 
rotate form will not be observed. 
Trochostoma Thomsonii affects a clay bottom, and 
is unquestionably a very sluggish animal; indeed its capacity 
of motion can be but limited; at least it will often keep 
motionless for days together when placed in a tub of sea- 
water for examination, and life would seem wholly extinct, 
were. not a fecal pellet seen now and again to pass out of the 
anal opening, accompanied by a scarcely perceptible change 
in the form of the tubular prolations on the oral disk. 
There is however no reason to Suppose that this animal 
passes the entire period of its existence in one spot, the 
force of ocean currents being: amply sufficient to float it 
from-place to place, since it may be easily given a rolling, 
swaying motion. 
Colour violet, sometimes light, sometimes dark, with 
a tinge of brown on the ventral surface. Longitudinal 
muscles a dirty yellow. The tubular prolations of the oral 
disk, as also the anterior portion of the body, generally 
pale violet. The smooth portion of the oral disk and 
the tentacles whitish-yellow. The caudiform portion pale 
yellowish-violet. In one or two specimens the colour was 
more of a greenish hue, relieved with dark-brown, almost 
black patches, Caudiform appendix white, 
faintly tinged with rosy-red, and the whole of the oral 
disk almost white, saving the tubular prolations, which were 
pale greenish. 
varying in size. 
Locality. 
Station 18; Station 33; Station 137. 
Generie Character. 
«Body long, cylindric; anterior extremity truncate. 
Oral disk furnished with, 15 tubular prolations, alternating 
with 15 oval-shaped depressions, in which are 15 papillary 
tentacula. Posterior extremity caudiform elongate. Anal 
opening surrounded by 5 dentelli. Skin exceedingly rugose. 
No suckers. Two intestinal appendices (respiratory trees) 
Specific Character. 
/ 
Tentacles rudimentary, furnished with 3 small papille, 
The calcareous cor- 
some being 
that in the middle being the largest. 
puseles in the skin varying in form and size, 
oval and some elliptic, and some occurring as comparatively 
large perforated plates, each with a corolla, their funda- 
mental form trifid, or rather three-armed. Colour of 
skin violet, tinged with brown on the ventral surface, and~ 
somewhat lighter at the posterior and anterior extremities. 
