Protistplankto 



111 



any rate, cannot l)o iilcntical to P. iiclhic'uliDii |',Kii(iii. as nicntio- 

 irmI liy r.iTsciii.i (L. 111). /'. tnsli/hiiii r. tjnilu .Sciimiii. is lui- 

 donljtodly another speeies. 



Very rare and very scarce; occmrrd tn-ctlicr with dccanic and 

 sontlicrn forms in Traniklybct ■■/■., 1!)00, (iou ni. Tiio same form 

 is very rare on the west coast of Norway: The Jiy Fiord of Ber- 

 >ren '7i 1901, O-iOO m.; Tlie Oster Fiord, % 1901, 25—50 m., 

 1(1(1 •_'(!(• in. 1 liave also seen it IViim the Stor Fiord in Sond- 

 moi-f (S y Miciiael Sars I'.Mio. st. ;!. KK) .'id uw. 



F. iwdiiucidatuni is, accordinij- to Ci.kvio, a sontliern tempc- 

 lato, oceanic species, distributed in the Atlantic from rather far 

 sDuth northwards to the neio-hhourhood of Iceland (rarely). 



P. Steittii Juno. 



.I.iuc. 1.. 91. p. .-JS. /'. Mirhaclis .Stein L. 135, p. 9, f. 9 — 

 11. non EnHii. Ci,. L. 40. p. ■2GS. 



Occurs in ([uite a larire number of the samples, but always 

 sparsely. The species seems to be absent during- the spring diatom 

 intiow. Accordini!' to Gran (L. G7) in small numbers in the Eids 

 Fiord and Ofoten in the months July — August 1899. 



In the tables it is reckoned together with another smaller form, 

 ■w liicli is probably speeitically ditferent from the genuine P. Ste'mii, 

 and seems to have a more northern distribution. 



D'tstribxition : Southern oceanic form, which, according to 

 Cleve, is widely distributed in the warmer (eastern) part of the 

 tempei-ate Atlantic, northwards to Greenland, Iceland and towards 

 iSpitzbergen. Very scarce round the Faeroe Islands. Also rare on 

 the west coast of Noi'\\-ay. where there occurs (at least) two diffe- 

 rent species. 



P. ovatiun (PorcH ) Scbi'tt. 



Fre{iuent, often numerous. Found by Gran on the northern 

 coasts of Norway, rather numerous at sevei'al places in the months 

 of . I uly— September 1898—99. 



Distribution: Seems to be an arctic and northern temperate 

 (boieal), cliiefly neritic (?) species, which is known from the coasts 

 of Western Europe, the North Sea, Skagerack, Cattegat, the Baltic, 

 the west coast of Norway, the Faeroe Islands, Iceland, Greenland 

 and Spitzbergen. Stationary on the coasts of Norway, being es- 

 pecially common on the west coast in the months of April and ]\Iay. 



Ccratinni Schrank. 



As most of the easily recognized forms of C. tripos are now, 

 by almost all plankton investigators, mentioned as distinct species, 

 I have thought it best to do so too, as far as possible. I am, how- 

 ever, inclhied to think that by so doing we get a basis which is 

 ratiier uncertain. On tiie other liand, it seems that one really goes 

 too far when one considers all ,, forms" of Ceratimn tripos (e. g. 

 balticum and macroceros) as one species. As, however, the so-cal- 

 led species are very difficult to characterize well (naturally), the 

 result will be that there will be numerous species, and one gets 

 into a hopeless chaos, as we have already seen in the case of one 

 author. According to my opinion, therefore, the only practical so- 

 lution will be to set up as few „species" as possible, but to clas- 

 sily the divergent forms as „varieties". It will, I think, for the 

 sake of clearness, also be necessary to arrange the varieties in 

 groups, as more new forms are apjjcai'ing. 



C. trii)os (0. K. !VIi;i.i,.) Nrrzsin. 



('. I. 'J. hidfinnn iSciiirr. 



Coinnion and generally in large quantities; durini.' the .spring 

 diatom intiow, iiowever, very much scarcer than at other times. 

 Found by Gran at several places on the north coast in the months 

 of July— October 1898-99, dually numerous. 



/>i.'<fn/iiiliijn : According to ('levk, widely distributed in the 

 w aimer i)ait id' the temi)erate Atlantic, from whence it extends 

 noithwards. V'eiy fVeiiuent on the coasts of the North Sea, Skage- 

 rack and Norway; as an exception, as far north as Spitzbergen. 

 Stationary on the coasts of Norway. 



The form which is found in the Baltic is, according to Ostex- 

 FELD, L. IIG, p. 58.3, 584, f. 132, 1.33, 134, somewhat different 

 to the North-Atlantic one. 



(". Inicephalum (('r..) Cl. 



('i,. L. 40, ]). 211. C', tripvs ntr bticephaJus Cl. !.. 40. p. .■i02, 

 f. 5. ('. f. (ircuatum (Gouiik.) Jorg. L. 91, p. 44. pi. 2. f. II, 

 non C. (iriuutum GocRR. L. 63, p. 25, pi. 2, f. 42. 



Seems to be a well characterized and little varying form, which 

 without (lifticulty can be considered as a separate species. Occurs 

 together with the preceding, and almost exactly corresponds to it 

 in freijucncy. 



Distribution: In all important respects, hke the preceding 

 species; but appears to be more westerly. Seems to be absent 

 round the Faeroe Islands, and is much loss frequent on the west 

 coast of Norway than the preceding species. 



C. bucepbalum (t'L.) Cl. rar. heterocampta Jokg. 



C. tripos t arcuatutii formu heterocampta Jorg. I^. 91. p. 44, 

 pi. 2, f. 12. C. tripos rar. ariefinum Cl. L. 3G, p. 13, pi. 7, f. 3. 



Not noticed in the samples from 1899; in .several .samples from 

 1900 and occasionally rather numerous. 



Distribution: Southern oceanic species, according to Clevk 

 (L. 40, p. 209) widely distributed in the warmer part of the 

 Atlantic and also known from the Indian Ocean. Frequent on the 

 west coast of Norway in 1898 in the months of September— De- 

 cembei'; singly in February. 



C. macroceros (Khhb.) Cl. 



Fio([neiit and numerous (less so during the spring diatom iiiHow), 

 but much .scarcer than the t\\o foregoing species. Found on the 

 northern coast together with them during the summer and autumn 

 1898—99 by Gran. 



Distribution: In the Atlantic, in all important respects like 

 C. bucqjhalum. Has not been found either round the Faeroe Is- 

 lands. All the year through on the west coast of Norway, but 

 much less frequent than C. tripos (maximum in summer). Occasion- 

 ally noticed at Spitzbergen (in the warmer waters). Also known 

 from the Indian Ocean. 



C. intermedium (Jorg.) 



C', macroceros fortna intermedia Jorg. L. 91, p. 42, pi. 1, f. 10. 

 C. tripos var. scotiea Ostenf. L. Ill, p. 57, nou ScHtJTT. C. hor- 

 ridum Gran L. 70, p. 194, non C. tripos var. horrida Cl. L. 46, 

 p. 302, f. 4. 



