WISCONSIN PHYTOPLANKTON 



KEY TO THE DIVISIONS. 



Motile phase dominant, rhizopodial or palmella phase rare . EUCHRYSOMONADINAE 

 Immobile phase dominant, motile phase known or unknown. 



Cells spherical to ovoid, embedded in a gelatinous envelope . . . HYDBUBINAE 

 Cells with pseudopodial processes ...................... RHIZOCHBYSIDINAE 



Division EUCHRYSOMONADINAE. 



Cell structure and organization as noted in the description of the 

 sub-class. Ciliate phase dominating the life history. Palmella or 

 rhizopodial phases known but not the general rule. 



KEY TO THE ORDERS. 



Motile phase with one fiagellum CHEOMULINALES 



Motile phase with two flagella. 



Flagella of the same length ISOCHBYSIDALES 



Flagella of unequal length OCHBOMONADALES 



Order CEROMUUNALES. 



Cells generally solitary, rarely colonial ; free-floating or sessile. Mo- 

 tile phase with a single apical flagellum. Chromatophores reticulate, 

 laminate, or disciform ; generally two in each cell. Apical contractile 

 vacuoles present or lacking. Cells either naked or with a definite, homo- 

 geneous or sculptured periplast. 



Reproduction by vegetative division of cells. Thick-walled resting 

 stages known in certain genera. 



KEY TO THE FAMILIES. 



Cells naked EUCHBOMULINACEAE 



Cells with a differentiated periplast , . MALLOMONADACEAB 



Family EUCHROMULINACEAE. 



Cells naked, without a differentiation of the periplast. Cells with 

 sharply defined disciform to laminate chromatophores, and without 

 contractile vacuoles. Flagellum single. 



There are several genera with many species in the family but only 

 one of them, Chrysamoeba, has been noted in the plankton of the state. 



