KUNGL. SV. VET. AKADEMIENS HANDLINGAR. BAND 57. N:Q 7. 



23 



winterly Sira-plankton, filling the waters in February with masses of Thalassiosirce (efr 

 Mr Gran's work and Series V in the following), only traces are left. 



Table 28. S. Extra II. 



57° 43' N., 



11° 7' 



E. 26. IV. 1913. 







o 



^ 



o3 



cä 



g 



g 



03 





W 



g 



3 







IJd 



o 





'■5 9 



S "*> 



.3. s-. 



•2 £ 



C ro S 



» 1) - 



O v, 



.2 



" 9 



s 



t, 



eS to 



"3 



a. 



P 



<D o 

 P, 



E £ 



>> 



°3 

 c 



is s 

 "&2 



c o £ 



■3.S 



2 c 

 c <s 



3 B..2 



W r- S 



fe O -O 



■" 0> 



"3 3 



c 

 'G 



.S—i, 



■5 o £ 

 ■a •*» a 



o 



W 



■» ca 



«•£ 

 ® E 



° 3 



o 5- 

 o ° E 





E-i-3 



3 



t» 



Q 







O -0 



3 



o-" 1 . 



> 



O 



* 



s c 







Ph c 







G. l>9 



21,37 



1G,77 





300 









100 



500 



900 



1,100 



2,000 



10 



4,18 



28,04 



22,27 



300 



1,600 



250 



100 



150 



50 



2,150 



1,750 



2,250 



4,200 



20 



4,59 



32, (i 3 



25,87 



200 



1,800 



50 





150 



400 



2,600 



700 



650 



1,500 



40 



4,70 



33,64 



26,66 



300 



1,100 









50 



1,300 



350 



250 



750 



Compared to the diatoms, the peridinians are quite subordinate, though by no 

 means rare. In the surface-current, only a few small Gymnodinia and Glenodinia occnr. 

 The flagellates, chiefly consisting of nnde forms (Gymnodinia), ha ve their maximum at a 

 somewhat deeper level than the diatoms, or 2300 ind. per 1 at 20 m. Even injusorians 

 badly support the conditions in the very surface, having their maximum of 4,200 ind. per 

 1 at 10 m. As usual, Mesodinium and small Laboece are the ruling forms amorig the Pro- 

 tozoa. 



Table 29. S/Skag 0. 57° 41' N., 11° 24' E. 26. IV. 1913. 



■C 

 ♦a 



a, 



<B 



R 



Tempera- 

 ture " C 



O 



>> 



o 



>> 



'3 



c 



CD 

 P 



Thalassiosira 

 Norden- 

 skiöldii 



03 

 u 



5 * 



o — 



a "g 



<3 b£> 



■å oS 

 — "*^ 

 a d 

 ** — 



pH té 



Leptocylin- 



dius danicus 



Rhizosolenia 



tieröensis 



Kluzosolenia 



hebetata 

 f. semispina 



Chaetoceras 

 debile 



Cliaetoceras 

 decipiens 



tn 



u tS 



s s 



o o> 



-^ 73 

 2 cs 



-3 



Cliaetoceras 

 sociale 



Diatoms 



total 

 numbers 







6,81 



20,99 



16.47 









(100)' 







200 



300 







850 



10 



4,71 



24,16 



19,16 









(5,8,00 



200 







250 







6,900 



20 



4,34 



26,94 



21,39 









106.900 



500 



350 





3,150 







172,400 



30 



4,68 



32,63 



25,86 



150 







15,750 



1,250 



1,550 



500 



12,450 





200 



32,900 



40 



5,28 



33,26 



26,29 



120 







2,720 



50 



440 



160 



1,100 





200 



5,100 



50 



5,18 



33,58 



26,.-, c. 





40 





1,240 



20 100 



160 



820 





280 



3,340 



60 



5,10 



33,77 



26.71 





40 



620 



980 



120 220 



200 



180 





240 



3,100 



73 



5,11 



34,45 



27,26 





150 



450 



1,050 





550 



200 



2,250 





2,700 



10,700 



Here, closer to the Swedish coast, the upper layer diluted by Baltic and land-water 

 is mightier, and accordingly Lepfocylindrus has its maximum first at 20 m, a depth that 

 does not, however, offer a sufficient supply of light for a maximal development. Also 

 the number of 166,900 ind. per 1, found here, does not come över half that of S. Extra II. 

 In other respeets, the general features are similar to those of S. Extra II. 



Peridiniales and Protozoa much as at Extra II, when the same kinds of water are 

 reached. The maximal numbers are still a little higher. From the maximum at 20 m, 

 there is a relatively slow deerease downwards. 



1 Mostly daniaged. more or less empty cells. 



