Microplankton from the Finnish Waters during the Month of May 1912. 7 



This diatom is not specified in the tables, being only distinguishable from the other 

 Chaetoceras-spores on closer examination and higher magnifying powers, than used when 

 counting. But it can be said with great certainty, that this species occurred in minimal 

 numbers compared with Chaetoceras Wighami, vvhich will be dealt with beneath. 



The spécimens drawn were found at station F 23 at the deptlis of and 10 mètres. 

 It is not noted from the other stations, but the possibility that is lias been overlooked 

 is not. improbable. 



Chaetoceras Wighami Brhüitw. 



(Fig. 4.) 



1856 a Brightwell, p. 108, pl. 7, f. 19—36. 

 1856b Brightwell, pl. S. f. 19-36. 



k 



Ï 



ti 



\ 



b. 



Fig. 4. Chaetoceras Wighami. 



a. Cells without spores. 



b. Cell in front-view. 



c. Resting- spores. 



1000 



1 



N:o 5. 



