Forskjellen mellem yoldia hyperborea, yoldia sapo- 
tilla og yoldia Umatula er saa liden, at de neppe 
bør opfattes som selvstendige arter. Som hovedform 
skulde vi anse yoldia hyperborea, da denne har det 
største udbredelsesomraade, og de to øvrige som varieteter 
og da yoldia sapotilla som en vestlig, amerikansk form og 
yoldia limatula som en væsentlig østlig europæisk; denne 
sidste forekommer dog ogsaa paa den amerikanske side. 
Yoldia myalis, Couthowy, har vi desværre ikke havt anled- 
ning til at undersøge, vi tør derfor ikke udtale os om 
denne, men er vi tilbøielig til at slutte os til Posselts for- 
mening, at den ikke har noget med oyenneynte tre former 
at gjore'). 
Yoldia hyperborea fandtes paa stat. 357, 125 fv. 
Norskøerne, 30 fy, Advent Bay, 20—40 fy., og Magda- 
lena Bay, 20—40 fv. De største exemplarer maalte: 30 
min, lang, 16 mm. hoi. 
Den typiske yoldia hyperborea er en hoiarktisk cir- 
cumpolar art, som er kjendt fra Spitsbergen, nordlige Rus- 
land, Novaja Semlja, Karahavet, Sibiriens ishavskyster, 
Beringshavet, arktisk Nordamerika og Grønland, Den 
bathymetriske udbredelse er 8—350 fy. Knipowitseh an- 
fører den som fossil fra det nordlige Rusland. 
The difference between Yoldia hyperborea, Y. sapo- 
tilla, and Y. Umatula is, small that they 
ought scarcely to be regarded as independent species. 
We should consider Y. hyperborea as the principal form, 
and the two others as varieties, Y. sapotill as a 
western, American form, and Y. Wmatula as mainly east- 
European. The latter, however, also occurs on the Ameri- 
We have unfortunately had no opportunity 
of examining Y. myalis, Couthouy, and are therefore 
unable to give an opinion on the subject; but we are in- 
clined to agree with Posselt in thinking that it is in no 
way connected with the three above-mentioned forms). 
indeed, so 
can side. 
Yoldia hyperborea was found at Station 357 in 125 
fathoms, off the Norwegian Islands (Spitsbergen) in 30 
fathoms, and in Advent Bay and Magdalena Bay in from 
20 to 40 fathoms. The largest specimens measured 30 
mm. in length, and 16 mm. in height. 
The typical Y. hyperborea is a high-arctic, cireum- 
polar species found off Spitsbergen, northern Russia 
Novaja Semlja, the Kara Sea, on the Siberian shores of 
the Arctic Ocean, in the Bering Sea, arctic North America, 
and Greenland. Its bathymetrical distribution is from 8 to 
350 fathoms. Knipowitsch states its occurrence as a fossil 
in northern Russia. 
Portlandia arctica, Gray. 
G. O. Sars, Moll. Reg. Arct. Norv., 1878, p. 37, Pl. 4, fig. 7 a 
b. 
Nucula arctica, Gray, Parry’s First Voyage, Suppl. to. App. 1824, p. 201. 
Yoldia — Torell, Spitsbergens Mollusker, 1859, p. 145. 
— —  M. Sars, Foss. Dyrelevninger, 1865, p. 145. 
Portlandia — 
Yoldia — 
Døde skaller af denne art fandtes paa stationerne 
312, 353 og 363. Da disse stationers dybde er 658 fy., 
1833 fv. og 260 fy., er der grund til at antage, at exem- 
plarerne er af drivisen ført ud paa dybet, thi portlandia 
arctica synes ikke at være nogen dybvandsform, dens bathy- 
metriske udbredelse er 5—100 fy. Til denne art har vi 
under nogen tvil ogsaa henført en ung portlandia (long. 
5 mm, alt 3 mm., crass. 2 mm.) fra stat. 290, 191 fy. 
Portlandia arctica er en høiarktisk, circumpolar art, 
som er kjendt fra Grønland, arktisk Amerika, Berings- 
havet, Sibiriens ishavskyster, Karahavet, Novaja Semlja, 
Hvidehavet og Spitsbergen. Ved Norges kyster synes den 
ikke mere at forekomme levende, subfossil er den derimod 
funden saavel ved Lofoten som ved vestkysten. Fossil er 
portlandia arctica kjendt fra Norge, Skotland, Grønland, 
Canada, Sibirien og det nordlige Rusland. 
Leche, Vega Exp. Vetensk. Iakttag., vol. 3, 1883, p. 444, Pl. 33, fig. 
18, 19. 
Empty shells of this species were found at Stations 
512, 353 and 363. As the depths at these stations are 
respectively 658, 1333, and 260 fathoms, there is reason 
to suppose that the specimens have been carried out by 
the drift-ice into deep water, for Portlandia arctica does 
not appear to be a deep-water form, its bathymetrical 
distribution being from 5 to 100 fathoms. There is also 
a young Portlandia (length 5 mm., height 3 mm., thickness 
2 mm.) from station 290 (191 fathoms), which we haye 
with some hesitation referred to this species. 
Portlandia arctica is a high-arctic, cireumpolar spe- 
cies, known in Greenland, arctic America, the Bering Sea, 
on the arctic shores of Siberia, in the Kara Sea, Novaja 
Semlja, the White Sea and Spitsbergen. It no longer 
seems to occur in a living state off the Norwegian coast; 
but on the other hand, it is found in a sub-fossil condition 
both off Lofoten and the west coast of Norway. Port- 
landia arctica is known as a fossil in Norway, Scotland, 
Greenland, Canada, Siberia and the north of Russia. 
1) Consp. Fau. Grænlandicæ; 1898, p. 31. 
| 
1) Consp. Fau. Grænlandica, 1898, p. 51. 
