62 



Conservation Department 



end of which a No. 20 piece of silk bolting cloth had been firmly 

 attached with a rubber band. Then the suspension was made up 

 with distilled water and formaldehyde as a preservative to stancl- 



%-'■ 



Liter uater sampler for naimoplaiikloii 



ard volume, 10 cc. in all cases. These 10 cc. samples were put into 

 homopathic vials and used for the counts. 



The one-liter samples of water were run at uniform speed 

 through a Foerst No. 14 centrifuge. The organisms were thus 

 obtained in a small volume of Avater to which was added suffici- 

 ent distilled water and formaUh^hyde to make the volume of sus- 

 pension 10 cc. in all cases. 



Enumeration of the organisms in both ''net" and "centrifuge" 

 plankton was accomplished as follows: The 10 cc. sample was 

 thoroughly shaken and with a ''Stempel" pipette 1 cc. was trans- 

 ferred to a Sedgwick-Rafter cell. The standard method of 10 



