WISCONSIN PHYTOPLANETON 



KEY TO THE SPECIES. 



Angles of cells never produced into processes. 

 Corners of cells without spines. 



Cells triangular T. MUTICUM 



Cells quadrangular T. MINIMUM 



Corners of cells with spines. 

 All cell corners in the same plane. 



Cells triangular T. TBIGONUM 



Cells with more than three angles. 



Cells with four angles T. REGULARE v. INCUS (p. p.) 



Cells with five angles T. CAUDATUM 



All cell corners not in the same plane. 

 Cells quadrangular. 



Pyramidal cells T. REGULABE 



Halves of cells twisted over one another. 

 Wall smooth. 



Angles delicately tapering T. VICTORIEAE var. MAJOK 



Angles strongly convex T. REGULARE var. TOBSUM (p. p.) 



Wall verrucose T. VERBUCOSUM 



Cells five-angled T. PENTAEDBICUM 



Angles at corners produced into processes. 



Processes always unbranched T. HASTATUH 



Processes always branched. 



Cells flattened and processes in the same plane. 



General outline of cell H-shaped T. CONSTRICUM 



General outline of cell not H-shaped. 



Processes long, conspicuously branched T. GBACELB 



Processes short, not conspicuously branched T. LOBUIATUM (p.p.) 



Cells isodiametric and processes not in the same plane. 



Processes short T. ENOBME 



Processes long. 



With 3-5 series of branchings T. LOBULATUM var. POLYFURCATUM 



Never more than three series of branchings. 

 Diameter of cells always greater than the length 



of the processes T. PLANCTONICUM 



Diameter of cell always less than the length of 



the processes T. LIMNETICUM 



TETRAEDRON MUTICUM var. PUNCTULATUM (Iteinsch) de Toni. PI. 23, 



Figs. 10-13. 



Sylloge algarum 1: 600. 1889. 



Polyedrium muticum var. punctulatum Reinsch, Notarisia 3: 498, pi. 4, 

 fig. 6. 1888. 



Cells small, triangular, somewhat flattened. Sides of cells convex in 

 front view. Corners sharp but without spines. Cell wall covered with 

 small granules. (Tychoplanktont). 



Diam. cells 15-20 /* ; thickness 8-10 //,. 



Beaver dam (rr), Deer (rrr), Sand (2) (IT). 



