SPIROGYRA.* 



I. General Characters. 



Observe with the naked eye. Note : 



1. Floating masses consisting of long, fine, green 



threads. 

 Take between the fingers and note the smooth, 



slippery feeling. 

 J^fount a small quantity , in water on a slide , cover , 



and examine with a low power. Note : 



2. Unbranched filaments. 



(a) The shape of the cells. 



(b) The way in which they are joined. 



(c) The difference between the terminal 



cell and the other cells of the fila- 

 ment. 

 With a high power observe : 



3. The form of the cells composing the filament. 



Focus carefully and determine what geo- 

 metrical form the cell most resembles. 



II. Structure. 



With D 2 examine : 



1. The cell-wall, (Which part is common to two 



cells ?) 



2. The protoplasm. 



* Spirogyra can often be found in slowly-running streams or 

 floating in the water of quiet pools. 



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