16 P. T. CLEVE, HYDROGRAFISKA UNDERSÖKNINGAR. 



Plate I. 



1. Choetoceros Schiittii Cl. a. filament with eudocysts, 500 times magnified. 



6. part of the terminal setse. 2000 times magnified. 



2. Chcetoceros debilis Cl. a. filament: b. cell in S.V. botli 500 times mag- 



nified. 



3. Chcetoceros didymus Ehb. a. filament without endocysts {Ch. mamillanus 



Cl.) b. cell in S.V. both 500 times magnified. c. part of the terminal 

 setse, 2000 times magnified. 



4. Chcetoceros didymus Ehb., filament witli endocysts, 500 times magnified. 



5. Chcetoceros curvisetus Cl. a. filament. b. cell in S.V. both 500 times 



magnified: c. part of the terminal setse. 2000 times magnified. 

 C. Cerataulina Beryonii H. Per., with oell-contents: 500 times magnified. 



Plate II. 



1. Guinardia flaccida Castr. H. Per. a. living frustule, 500 times mag- 



nified. 



2. Chcetoceros distans Cl. var. a. filament. 500 times magnified b. part of 



the terminal setse, 2000 times magnified. 



3. Choetoceros compressxis Laudee a. filament Avith cell-contents b. cell in 



S.V. c. filament with some coarse setse d. cell with coarse sets in S.V. 

 all 500 times magnified. 



4. Leptocylindrns danicus Cl. Filament with cell-coatents. 5. Uried and 



calcinated filament both 500 times magnified. 



