122 



Aquatic Organisms 



mud after the water has receded, dotting the siirface 

 thickly, as with greenish beads of dew. 



The water net a?id its allies — The water net (Hydro- 

 dictyon) wherever found is sure to attract attention by 

 its curious form. It is a cyhndric sheet of lace-Hke 

 tissue, composed of slender green cells that meet at 



Fig. 43. A rather irregular portion of a sheet of water net 



{Hydrodictyon) 



their ends, usually by threes, forming hexagonal meshes 

 like bobbinet (fig. 43). Such colonies may be as broad 

 as one's hand, or microscopic, or of any intermediate 

 size; for curiously enough, cell division and cell 

 growth are segregated in time. New colonies are 

 formed by repeated division of the contents of single 



