416 Canadian Record of Science 



Scenedesmus obliquus, Turp. 



Colonies of 4-8 cells, cells fusiform with acute 

 ends, usually in a single series. 5-27 x 3-9 micr. 

 Every locality. 



S. denticulatus, Lagerheim. 



Colonies, 4-8 cells, in a nearly straight line. 4-5 



micr. wide, to 15 micr. long, each end with two 



minute teeth. 

 Every locality. 



S. quadricauda, Turp. 



Colonies of 2-8 cells, oblong-cylindric with rounded 

 ends, 9-33 x 3-12 micr. arranged in a single 

 series, end cells with long filiform projections. 



Every locality. 



Crucigenia rectangularis, A. Br. 



Cells 4-6 x 5-7 micr. 4-8-16-32 in a colony 13 to 35 

 micr. square with rounded angles, always in 

 groups of 4, cells oval or oblong, touching near 

 the outer end. 



Amherst Park, Back River. 



Selenastrum minutum, Nag. 



Cells crescent shaped, usually uniformly curved. 



7-9 micr. from tip to tip, 2-3 micr. wide at 



middle, cells usually free. 

 Back River, Amherst Park. 



Kirchneriella lunaris, Kirchner. 



Cells crescent shaped with rounded ends. 3-5 



micr. diam. at middle, 6-10 micr. long. 

 Mount Royal, Amherst Park. 



Family 3. Hydrodictyacese. 



Hydrodictyon reticulatum (L.). 



Cells usually several diameters long, length up to 



