fra Amerikas nord- og østkyst indtil New England, Gron- 
land, Island, Spitsbergen, Murmankysten, Barentshavet, 
Novaja Semlja, Karahavet og videre østover indtil Cha- 
tangabugten. Den bathymetriske udbredelse er 380—1456 
fv. Fossil er arca glacialis kjendt fra Grønland, Nord- 
amerika, Shetlandsøerne, Skandinavien, nordlige Rusland 
og Sicilien. 
also found off the north coast of North America, and the 
east coast down to New England, im Greenland, Iceland, 
Spitsbergen, on the Murman Coast, in the Barents Sea, 
Noyaja Semlja, the Kara Sea, and eastwards as far as 
Chatanga Bay, Its bathymetrical distribution is from 30 
to 1456 fathoms. Arca glacialis is found as a fossil in 
Greenland, North America, Shetland Isles, Scandinavia, 
the north of Russia, and Sicily. 
Arca frielei, Jeftreys. 
Arca frielei, Jeffreys, m. s. Friele, Nyt Mag. f. Naturvidensk., vol. 28, 1877, p. 2. 
Arca frielei kan ikke saasom af Verrillt) og Kobelt*) 
betragtes som en varietet af arca pectunculoides, thi fra 
denne art og dens varieteter udmærker den sig ved sin 
tilspidsede stærkt triangulære form. Hos arca frielei er 
endvidere de fra umbonerne udgaaende ribber mere frem- 
trædende og mindre talrige. Skallets vel udviklede haar- 
beklædning er endvidere af en grovere struktur end hos 
arca pectunculoides. Verrill synes ganske at have misopfattet 
denne art; vi tør ikke med bestemthed paastaa, at det er 
area pectunculoides han har afbildet, men under ingen om- 
stændigheder er det formen /rielei. Uoyerensstemmelsen 
mellem Verrill's og Jeffreys's tegninger har forøvrigt ogsaa 
Locard3) været opmærksom paa; han bemærker med rette, 
at han har vanskelig for at identificere dem. 
Under navnet arca imitata beskriver og afbilder 
E. A. Smith en bivaly, som ,Challenger* erholdt i den 
nordlige del af Det stille ocean (station 244, 2900 fy.). 
Denne art har den samme form, den samme striering af 
skallet o, s. v. som arca frielei, og baade beskrivelse og 
tegning passer paa denne, hvorfor vi maa anse dem for 
identiske. 
Findested. Stationerne 40, 51, 53, 
303, 312 og 343. Dybde 658—1539 fy. 
Arten er tidligere funden af ,,Porcupine* i Færø- 
kanalen (1869, stat. 65, 345 fv.). ,,Caudan* har den fra 
Biskayerbugten, 239 fv., , Hirondelle* og , Princesse Alice* 
fra Azorerne (691—851 fv.), ,Travailleur* fra kysten af 
Senegambien, 55 fv., og ,Challenger* fra Det stille ocean, 
Denne sidste localitet synes at tyde paa, at denne dyb- 
vandsart har en kosmopolitisk udbredelse. Den bathy- 
metriske udbredelse er 55—2900 fy. 
-o9 
248, 283, 295, 
Trans. Connecticut Acad,, vol. 5, 1882, p. 474, tab. 44, fig. 5, 6. 
Mart. Chemn. Conch. Cab,, vol. 8, part 2, 1891, p. 213. 
Moll. Test. Exp. Sci., ,, Pravailleur* & , Talisman", vol, 2, 1898, 
p. 320. 
Ww 
Se Ss | 
Jeffreys, Proc. Zool Soc., 1879, p. 573, Pl. 45, fig. 4, 4a. 
Friele, Jahrb. Deut. Mal. Gesell., vol. 6, 1879, p. 266, PI. 4, fig. 9. 
imitata, Smith, Rep. Sci. Res. Challenger Exp. Zool., vol. 13, part. 85, 1885, p. 321. 
It is impossible to regard Arca frielei, as Verrill') 
and Kobelt?) have done, as a variety of Arca pectunculoides, 
for it differs from that species and its varieties in its 
pointed, very triangular shape. In Arca frielet, moreover, 
the ribs issuing from the umbones are more prominent and 
less numerous. Further, the well-developed hairy covering 
of the shell is of a coarser structure than in A. pectun- 
culoides. Verrill seems to have altogether misunderstood 
this species, We would not venture to assert that it is 
A. pectunculoides that he has figured, but at any rate it is 
not A. frielei. Locard*) has also noticed the difference be- 
tween Verrill’s and Jeffreys’s drawings. He justly remarks 
that he has a difficulty in identifying them. 
BE. A. Smith describes and figures under the name of 
Arca imitata, a bivalve found by the ‘Challenger’ in the 
northern part of the Pacific (Station 244; 2900 fathoms). 
This species has the same shape, the same striation of 
the valve, etc. as A. frielei, which answers in every way 
both to the description and the drawing. We may there- 
fore regard them as identical, 
Locality. Stations 40, 51, 53, 248, 283, 295, 303, 
312, and 353. Depth 658—1539 fathoms. 
The species has been found by the ‘Porcupine’ in 
the Faroe Channel (1869, Station 65; 345 fathoms), the 
‘Oaudan’ in the Bay of Biscay (239 fathoms), the *Hiron- 
delle’ and the ‘Princess Alice’ in the Azores (691—851 
fathoms), the ‘Trayailleur’ off the coast of Senegambia (55 
fathoms), and the ‘Challenger’ in the Pacific. The last- 
named locality seems to indicate that this deep-water spe- 
cies has a cosmopolitan distribution. Its bathymetrical 
distribution is from 55 to 2900 fathoms. 
1) Trans. Connecticut Akad. Vol. 5, 1882, p. 574, Pl. X LIV, figs. 5, 6- 
2) Mart. Chemn. Conch. Cab. Vol. 8, part 2, 1891, p. 213. 
3 Moll. Test. Exp. Sci. ‘Travailleur’ & ‘Talisman’, Vol. II, 1898, 
på 320% 
