Plancton 81 



Study 16 

 PLANCTON 



Work Program: 



1. A laboratory examination of a fresh catch of surface plancton from a lake or pond 



(obtained by drawing a towing net of No. 12 silk bolting cloth through the water: 

 should be used at once after taking, so that the activities and natural colors of 

 the living organisms may be noted).* 



2. Reading in Life of I til and Waters, p. 18, 242-249 and 295-312. Also, such reference 



works on plancton as may be available. 



For Record include: 



1. An annotated list of the plancton organisms found arranged under the following 

 headings: 



I. Plants — with notes on size, color, relative abundance, growth habit and lice 



aggregation (illustrate these with simple diagrams), flotation devices, etc. 



Diatoms. 



Desmids. 



Blue greens. 



Green algae. 



Miscellaneous plant fragments. 



II. Animals — with notes on size, relative abundance, feeding habits, swimming 



habits, egg-carrying habits, etc. 



Protozoans. 



Rotifers. 



Crustaceans. 



Miscellaneous animals and animal products (eggs, statoblasts, shells, etc.)- 



* To concentrate plancton, pour the water containing it through fine silk bolting cloth in a funnel whose con- 

 verging sides dip below the surface of water in an overflowing jar. Take the concentrate from the funnel with 

 a dropping tube, and mount on slides for the microscope. 



