Diatom-. 



195 



b. Diatoms in Bottom Samples from Lofoten and Vesteraalen. 



I-'.. J0RGENS1 \. 



Iii the following pages an account is given of the diatoms con- 

 tained in some bottom samples from the following Idealities in Lo- 

 foten and Vesteraalen; 



Moskenstrommen, — ISO m. (together with plankton), 



Stamsund, — 150 m. (together with plankton), 



Svolvaer harbour, 10—15 m., 



The Ostnes Fiord, 10 — 20 m., 



Brettesnes— Skroven, 350—400 m.. 



Mouth of the Raftsnnd, 250—300 m„ 



Stene in Bo, 10 m., 



Gaukvsere, 0—180 m. (together with plankton). 



Two of these, the samples from Brettesnes — Skroven and from 

 Raftsund, were poor and consisted perhaps only of dead specimens, 

 a good many of which naturally originate from the plankton. The 

 samples from Moskenstrommen, Stamsund and Gaukvsero were taken 

 together with plankton. 



The working through of bottom samples is a very troublesome 

 and lengthy task, when it is dene as it should be. As there was. 

 however, not time enough to investigate the samples in the manner 

 I consider the right one, and as -- on the other hand - it was 

 of some importance, to be able rightly to interprete the plankton, 

 to gain a preliminary knowledge of the bottom flora, I have con- 

 tented myself with the method usually adopted, and have studied 

 the species from the valves in slides. For this purpose the material — 

 together with a richer one from the west coast of Norway — has 

 been prepared as slides by Mr. Thum of Leipzig, in his well-known 

 perfect way. 



For this reason, it has not been possible to discern between 

 living '(recent) and fossil species. 



The species occurring in the plankton are in detail dealt with 

 in another chapter of this work (pp. 90—108). Nevertheless, to 

 avoid arbitrariness, I have not omitted the plankton species, but 

 have in such eases mentioned them as originating from the plankton. 



List of the species observed. 

 I. Oeio-'biE'ioae Schutt. 



i. Coscinodiscese. 



Coscinodiscus Eheb. 

 C. nitidus Geeg. 



Cf. above p. 95. 



Somewhat rare: Moskenstrommen r. Stamsund r, Raftsund r, 

 Stene r, Gaukviero r. 



Distribution: Western Europe; Balearic Islands. Greenland 

 and Finmark (Cleve). Warmer coasts of America, Asia and 

 Australia. 



C. appollinis Eiirr. (1844). 

 Kurd. Mikrogeologie pi. 35 A, XXII, I'. 4. 



rnr. com.pa.Cta Uattk. Rev. of Coscinod. p. 579. 

 < . scintillans (Gekv.) A. Schmidt Nords. Diat. p. ill, [.I. 3, f. 33. 



Differs from the main species (= C. scintillans Grev.) in 

 having the puncta distinctly smaller towards the margin, more 

 numerous radial rows, the shortened ones being longer than usual. 

 Probably is a separate species. 



Rare: Moskenstrommen -f-, Stamsund r. Svolvaer r. Stene r. 



Cose, nitidus A- Schm. Nords. Diat. pi. 111. f. 32 does not 

 show the irregular distribution of the puneta that is characteristic 

 of the preceding species. This form occurs in in\ material together 

 with the one figured I. e. f. 33 and has a similar radiate structure, 

 only much coarser. 



Distribution: The variety is only known from Solsvik (wesl 

 of Bergen, Norway). The main species, which has not been found 

 by us, occurs in the antarctic regions. 



C. eoncarus Eheb. Geeg 

 Geeg. Diat. of Clyde L857. p. 500, pi. X, f. 47. Ehrb. Mikrogeol., pi. 21. f. I 



lion pi. 18, f. 38. 



Hardly belongs to the genus Coscinodiscus. Rattray 1. c. p. 

 470 remarks that the girdle aspect of this species answers to F.n- 

 iHitijn ocnuiica Ehrb. (cfr. Mikrogeologie pi. 35 A, XXYIII figs. 6, 

 7; A. Schmidt Atlas pi. 65, figs. 10 — 15). 



Very rare: Gaukvaer0 r. Diameter 86 ;>. : 2 areoles on 10 |i; 

 border sharply defined, nearly 3 p. broad. 



Distribution: Western Europe: Balearic Islands, Black Sea. 

 Sea of Kara (Cleve). Warmer, coasts of America and Asia. 



C. leptopus Gei \. 



Van ETeueCK Synops. pi. 131, tin-. 5 — li. 



Rare: Raftsund r. Diameter 55 ;>-: •"> areoles on 10 :>■. Re- 

 markable for the minute areoles on the border, like those in the 

 genuine C. tinnitus Ehrb. It differs on the whole from the latter 

 species only in possessing the pseudonodule. 



Coscinosira polychorda Gran and the variety of Coscinodiscus 

 tinnitus mentioned below have a much finer structure and less re- 

 gularly straight rows of areoles. 



Distribution: Mediterranean. Southern Atlantic, Pacific Ocean, 

 Indian Ocean. 



C. lineatus Ehrb., rar. 



('!'. above p. Hi'. 



Rare: Stamsund. r. Finer structure than in the genuine <'. 

 lineatus. Small; 1\- — 8 areoles on lu \>.. Border narrow, striate, 

 15 stria' on 10 |i. Areoles near the border somewhat smaller. 

 Secondary rows somewhat tlexuose. 



In the sample from Svolvaer a verj similar specimen was 

 found, only with a little liner structure and marginal spines. This 



