include P. Drijgalslii. is also an arctic form, which has been found 

 at several places near Spitzbei'gen and Greenland. 



V. subarctica Jørg. n. var. 

 (PL XVIU, fig. 118). 



The house is broadest at the foremost thickened ring, which 

 is very pi'ominent. The width at the second ring is a little less, 

 decreasing evenly and gradually to the third ring. Behind this, it 

 becomes quickly rounded off nearly spherically (though slightly 

 narrowed off conically nearest the last ring). The wall is very 

 much thickened at the foremost ring. The distance between this 

 and the next ring is equal to, or a little less than, the half of the 

 distance between the two last (so that the two foremost )ings ai'e 

 comparatively near each othei-). 



Teeth small, about 36 — 40. 



Length (of the individual illustrated) \)i> \>-, width of 1st ring 

 76 [i, of 2nd 71, of 3rd 56 \>.. 



The difference from P. aretica Brandt (L. 16, p. 60, pi. 3, 

 f. 17) is only slight. My form is smaller and is rather different 

 in appearance at the hinder part. The mouth is also quite different 

 and the teeth much smaller. On the other hand, there is a remark- 

 able agreement in the very prominent foremost I'ing and its distance 

 fi'om the second. 



I dare not, at present, declare my form to be identical with 

 Brandt's, with which I am as yet too imperfectly acquainted. 



Very rare, only found sparsely iu 6 samples: Lyngen I, 

 0—115 m., Lyngen II, 0—250 m.. Lyngen III, 0—50 m., "A 

 1899; Malangen, -7i 1899, 0-300 m.; Tranødybet, ^2 1899, 

 0—200 m.; the Midvær Fiord % 1900, 0—25 m. 



Didrihution: The very closely allied P. aretica has been 

 found in Davis' Strait, the Labrador Current, near East Greenland 

 and in the sea west of Nowaja Zemlja (Cleve L. 40, p. 1 18). 

 Undoubtedly an arctic species, hardly native with us. 



C.yttai'oey«'lis fol. 

 C. norveøcn (Dad.) Jørg. 



Cfr. Jørgensen L. 9o, \). 28. 



Only once found: Hola, Hvolva^i-, "/.', 1899, i-athei' numerous. 

 Slips easily through the net. 



Distribution: Rather I'are, always in small numbers, on the 

 west coast of Noi'way. This form and tho.se closely allied to it, 

 C. gracilis (Brandt) and C', minuta (Brandt), are kno^\'n from 

 West and East Greenland, the Ijabrador Current, Jan Mayen, 

 Iceland, Baren Island and Spitzbergen. Arctic (and boreal?) 

 species. Its distribution is probably insufficiently known, as it is 

 so small that it only occasionally is retained by the net. 



C. serrata (Møii.) Brandt. 



(July onc.i^ found : Tnuiodybet, '-'-'A 1900, 0--600 m., vv. 



Didiihntion: Fi'cquent on the west coast of Norway, in the 

 summer and autumn. Also found in the summer on the north 

 coasts of Norway (Tromsø, Aurivillius). According to Clevk (L. 

 40, p. 113) a southern noritie form, disti'ibutcd from the Cape of 

 Ciood Hope to Scotland. 



C. denticulata (Ehrb.) Fol. 



Cfr. Jørgensen L. 90. p. 31 and L. 92, p. 4 etc. 



Many forms occurred, the most important of which are entered 

 in the tables. As a whole, the species was very frequent, often 

 numerous; only, at the peiiod of the diatom inflow, very scarce or 

 entirely absent in the outer districts. 



Distribution: The majority of the numerous forms which belong 

 here seem to be oceanic, arctic and boreal. The species is widely 

 distributed over the northern part of the Atlantic, in the Arctic 

 Ocean and on the arctic and northern temperate coasts. Frequent 

 in the sea on the north coast of Scotland, August 1903 (L. 18, 

 1903—1904, nr. 1). According to Cleve (L. 40, p. 109) also in 

 Behrina' Sea. 



a typica Jørg. 



Jørgensen L. 90, p. 31, pi. 2, f. 13, 15. 



This form, which is the most frequent on the west coast of 

 Norway, was not often found in the present material. 



Distribution: Perhaps a neritic, northern temperate form. 

 Most frequent in the summer and autumn on the west coast of 

 Norway. 



var, gigatitea (Brandt) Cleve. 



Rare and scarce. 



Distribution: Possibly a boreal (and arctic?) oceanic form. 

 Known from the northern part of the Atlantic to Greenland and 

 Spitzbergen. Also mentioned from the Labrador Current. 



Tar. robusta Jørg. 



Jørgensen L. 92, p. 13, pi. 3, f. 22. 



Only once found: Kvænangen, "Vi 1899, — 140 m. 



Distrihution : Only found in the sea between Norway (Tromsø) 

 and Jan Mayen, in small numbers. Possibly boi'eal. Perhaps rar. 

 gigantea (Brandt) p.p. also belongs here. 



var. suhrotiiiulata Jørg. 



.Iøugensen L. 90, p. 34, pi. 2, figs. 20, 21. 

 Rare and scarce. 



Distribution: Not so rare on the west coast of Norway in 

 the summer (1898). Possibly a neritic, northern temperate species. 



rar. eylindrica Jørg. 



Jørgensen L. 90, p. 33, pi. 2, figs. 17, 18. 

 Rather rare, iicvei' numci'ous. 



JJistriliiilioir. Not rai'c on the west coast of Norway in the 

 suumuT anil autiuun. Possibly iiciitic, northern temperate species. 



tar. elongata Jørg. 



Jørgensen L. 92, p. 14, pi. 3, tigs. 23, 24. 

 Rather rare, almost always in small numbers. 

 Disiriliittion: Known from the sea between Tromsø and Jan 

 Mayen (numerous, 1898). Seems to be a boreal, oceanic form. 



