WISCONSIN PHTTOPLANKTON 77 



ing 1-2 parietal, diseifonn to bell-shaped, golden-brown chromatophores 

 with, smooth or irregular margins. (Euplanktont). 

 Cells 7.2-9.6 /* in diam. ; colonies 50-250 //, in diam. 



Carson (ss), Clear Crooked (c), Crawling Stone (rr),. Devils (1) (ss), Hill- 

 man (rr), Jennie (r), Mary (s), Mendota (sss), Pokegama (1) (rr), Sand 

 (4) (rr), Shell (ss), Silver (2) (s), White Sand (rr). 



Division RHIZOCHRYSIDINAE. 



Algae that are known in the rhizopodial stage only, although the 

 power to form a motile phase is presumed to be present. Cells solitary 

 or in small colonies, always free-floating. Cells with rhizopodial pro- 

 cesses and with or without a differentiated periplast. Cells with 1-2 

 golden-brown chromatophores, and with or without numerous vacuoles. 



Reproduction by vegetative cell division. 



This is an entirely artificial group where rhizopodial forms are placed 

 pending further elucidation of their life histories. Since the group 

 contains such doubtful forms no attempt has been made to differentiate 

 the orders and families. 



KEY TO THE GENERA. 



Cells solitary or in irregular colonies RHIZOCHBYSIS 



Cells joined in a linear series to form colonies CHBYSIDASTBUM 



KEIZOCHRYSIS Pascher 1913. 



Cells free-floating, solitary or in colonies that are naked or enclosed 

 by a gelatinous sheath. Cells without a differentiation of the. periplast 

 but with few or numerous, delicate, pseudopodial processes. Cells with 

 one or two golden-brown chromatophores and numerous vacuoles, of 

 small size when united in colonies. 



Rhizochrysis limnetica sp. nov. PI. 14, Fig. 6. 



Cells solitary, free-floating, without a differentiation of the periplast 

 but with numerous spicule-like processes extending in all directions. 

 Cells approximately spherical, with one golden-brown chromatophore 

 and numerous vacuoles. (Euplanktont). 



Diam. cells (without processes) 35-45 p.. 



Beasley (sss), Birch Island (rr), Crawling Stone (rr), Deer (rr), Diamond 

 (rrr), Half Moon (rr), Horse (rr), Kitten (sss), Lac du Flambeau (r), Long 

 (3) (sss), Marl (rrr), Nemahbin (ss), Oconomowoe (rr), Okauchee (rrr), 



