WISCONSIN PHTTOPLANKTON 91 



single contractile vacuole at their base. Palmella stages frequent and 

 usually containing 4^-8 cells. (Euplanktont). 

 Cells 5-10 p broad. 



Crawling Stone (rr). 



Chlamydomonas epiphytica sp. nov. PI. 16, Figs. 11-13. 



Cells spherical to pyriform, with a very pronounced anterior beak. 

 Chloroplast cup-shaped, forming a thin layer next to the cell wall, with 

 a single pyrenoid at the posterior end. Eyespot conspicuous, disciform, 

 at the anterior end of the cell. Cilia more than twice as long as the 

 cell. Cells frequently coming to rest in the gelatinous envelope of 

 Microcystis colonies but not losing the eyespot and usually retaining 

 the cilia. (Euplanktont). 



Cells 7-8 ju, broad, 8-9 /* long ; cilia 20-25 /* long. 



Elizabeth (s), Mary (sss). 



The alga is frequently found in the gelatinous envelope of Microcystis 

 colonies and suggests an epiphytic diaracium but the presence of cilia 

 shows that it is a Chlamydomonas. 



CHLAMYDOMONAS SNOWH Printz. PI. 16, Figs. 9-10. 



Skr. Vidensk.-Selsk. 1 Kristiana, Mat.-Naturv. Kl. 1913 1 : No. 6: 18. 1914. 



Chlamydomonas communis Snow, Bull. U. S. Fish Comm. 22: 388, pi. 1, 

 figs. IP-IP. 1903. 



Cells motile but frequently forming palmella stages containing a 

 considerable number of cells. Cell shape ovoid to ellipsoid, with a very 

 inconspicuous anterior beak. Chloroplast cup-shaped, massive in the 

 posterior portion, with one pyrenoid at the center of the cell. Cilia 

 slightly longer than the cell; eyespot inconspicuous, variable in posi- 

 tion. (Facultative planktont). 



Cells 6.5-8 /JL broad, 10-15 /* long. 



Nancy (rr). 



Chlamydomonas dinobryoni sp. nov. PI. 16, Figs. 5-7. 



Cells rarely free-swimming, generally in large numbers and filling 

 the empty receptacles of Dindbryon colonies. Cells small, ovoid to pyri- 

 form in shape, without an anterior beak; with two short cilia at the 

 anterior end. Chloroplast disciform to hemispherical, basal or lateral 

 in position, containing a pyrenoid. Eyespot and contractile vacuoles 

 not observed. (Euplanktont). 



Cells 2-3 ju, broad, 3.5-5 p long; cilia 6-8 ^ long. 

 Lac du Flambeau (ss), Long (3) (s), Pokegama (2) (r). 



