months, most frequent in November (1898). According to Cleve, 

 also known from Hudson's Bay. 



R. setigera Brightw. 



Only once found: — '■'A 1899 Malangen, in a deep water 

 sample. 



Distribution : Neritic species, scarcely to be considered native 

 to the Norwegian coasts. Known from the coasts of France, Eng- 

 land and Scotland, as well as from the Skagerack and the west 

 coast of Norway. Gives the impression of being brought to the 

 latter from the southern coasts in the autumn, but also occurs in 

 the winter and spring months, but always in small numbers. Has 

 therefore probably also a (smaller) northern area of distribution. (Is 

 reckoned by Cleve to be a southern and northern ueritic species). 



C'oi'l'tliroii liystrix Hens. 



Very rare and only scarce. 



Distrihution : Comes to us as a southern oceanic form. On 

 the west coast of Norway also very rare (1898). Rare too near the 

 Faeroe Isles. Distributed in the Northern temperate Atlantic up 

 to Iceland and East Greenland. 



C'liwtoeei'os Ehrb. 



C. horealis Bail. 



Occurs in numerous samples, but always in small numbers. 



Didrihut'ion: Arctic and northern temperate, oceanic form, 

 wliich often occurs in very large numbers in arctic waters and in 

 the boundaries between these and the Atlantic. On the west coast 

 of Norway, 1898, more or less frequent in most months, especially 

 in May — July. A similar state of things was found at the Faeroe 

 Isles. 



C. deijsus Cl. 



Does not seem to he fi'e([uent. Is, however, perhaps often 

 mistaken for othei- forms. 



Distrihution: Appeal's to be a southern form. 



C. dcnsus 



rudis ('l 



The form entered in the tables for 1900 under this name is 

 uKcc^rtain. Although in side view as well as by its unu.sually coarse 

 and coarsely dentate awns recalling the illustration of Chaetoæros 

 hoycidis var. rudis in Cleve's Phytoplankton (L. 27) pi. 1, f. .5, it 

 diti'ers in some other points; neither do I know the shape of the 

 terminal awns nor their direction in Ceeve's species. 



It is, at any rate, very improbable that my species is the same 

 as C. coarctatus Laud., which Cleve (L. 4(i, p. .306) mentions as 

 being the right name for the foini which he previously called C. 

 horealis var. rudis. 



C. danivits (Jl. 



Very rare and only scarce. Only found in a few samples: 

 *li 1899, Helle, 0—3 m., -7:) 1900, HOla, 0—50 m. and the Sal- 

 ten Fiord, V4 1900. 



Distrihution: The noilhern European coasts of the Atlantic 



and its arms as far as the Baltic. On the west coast of Norway 

 it is found most montlis, but most fi-equeutly in the summer. 



C, criophilus Castr. 



Cfr. E. Jørgensen L. 92. 



Only once found: '-■'A 1899, in the sea off IngO. 



Distribution : Appears to be a decidedly arctic species, wliich 

 often occurs in very large quantities in the arctic waters and in 

 their boundary towaids the Atlantic. Its distribution is, howevei-, 

 not sufficiently known, as it has been confused with the following 

 species. 



C. coiirolutus Castr. 



Cfr. E. Jørgensen L. 92. 



Frequent during the inflow of diatoms in spring, often rather 

 numerous. Otherwise scarce. 



Distrihution: Appears to be an arctic and boreal species, 

 which often occurs in large quantities in the arctic waters and then- 

 boundary towards the Atlantic (Jan Mayen 1897). On the west 

 coast of Norway found all the yeai- round, but always in small 

 numbers. It may be possible that this species is neritic rather 

 than oceanic. Frequent in May 1903 in the English Channel 

 (L. IS, IV). 



C. atlanticus Cl. 



Frequent, but only as an exception somewhat numerous, gener- 

 ally only scarce. 



Distribution: Ai'ctic and boreal oceanic form, often occurring 

 in vei'y large quantities in the arctic waters and their boundary 

 towards the Atlantic. (Cfr. E. Jørgensen L. 92). On the west 

 coast of Norway found in most months, but, as a rule, scarce. 

 Common off the Faei'iies in spring. 



C. dcciph-ns: Cl. 



Frequent during the diatom inflow in spring, otlierwise rare 

 and scarce. Decidedly more frequent in the samples of 1900 than in 

 those of 1899. 



Distribution: Arctic and boreal oceanic form which seems to 

 bear the change from the arctic to the Atlantic watci-s particularly 

 well. Often occurs in abundance in the boundary waters. On the 

 west coast of Norway, rather connnon, reaching its maximum in 

 Api'il (1898). This also the case at the Faeroe Islands. Also 

 very abundant on the west coast of Norway in the montlis July — 

 September (1898). 



C. teres ('l. 



Frequent in the samples, but always in small numbers. 



Distribution: Arctic (oceanic?) and boreal form, . which only 

 as an exception appears to be found more numerous. On the west 

 coast of Norway very scarce, though found in most months. Near 

 the Faeroe Islands frequent in the months March — .liuic, at other 

 times rare. At Ona (cfr. Gran L. 70, p. 178) fi'oni March to 

 July, most frequent hi April. 



My opinion is that this is an oceanic species I'ather than a 

 neritic one, and is hardly native on our coasts. (Has been repeat- 

 edly found with endocysts, therefore, according to Guan, neritic, 

 hut a hinii which may often drift far out into the open sea). 



