WISCONSIN PHYTOPLANKTON HI 



Cells with 6-25 chloroplasts. 



Polar nodules conspicuous, 12-25 chloroplasts O. SOLITABIA 



Polar nodules not prominent, 4-10 chloroplasts O. CBASSA 



1-2 (rarely 4) chloroplasts in each cell. 



Cells elliptic, length iy 2 times breadth O. LACUSTRIS 



Cells oblong-cylindrical, length 2-3 times breadth 0. SUBMAKINA 



Cells without polar nodules. 



Poles of cells rounded. 



Length of cells less than 12 fj. O. PUSH-LA 



Length of cells more than 12 IL. 



1-4 chloroplasts in each cell O. BOBGEI 



8-10 chloroplasts in each cell O. ET.UPTICA 



Poles of cells pointed. 



Old cell wall enclosing colonies rounded O. PABVA 



Old cell wall enclosing colony sharply pointed . .0. GLOEOCYSTIFOBMIS 



OOCYSTIS PUSILLA Hansgirg. PI. 22, Fig. 3. 



Sitzbr. d. k. bohm. Ges. d. Wiss. in Prag, Jahrgang 1890: 9. 1890; Printz, Nyt. 

 Mag. f. Naturvidensk. 51: 181, pi. 4, figs. 31-32. 1913. 



Cells cylindrical, poles rounded and without nodules. Chloroplasts 

 2-3, parietal, laminate, without pyrenoids. Temporary colonies con- 

 taining 2-^4-8 cells. ( Tychoplanktont) . 



Diam. cells 4.5-6.5 /j. ; length 8-12 /*. 



Tied Canoe (rr). 



OOCYSTIS BORGEI Snow. PI. 22, Fig. 4. 

 Bull. U. S. Fish Comm. 22: 379, pi. 2, figs. VIP-VII 6 . 1903. 



Cells broadly elliptic, length l^ times the breadth; poles rounded 

 but without nodules. Chloroplasts 1-4, parietal, laminate, each con- 

 taining a single pyrenoid. Cells solitary or in families of 2-4-8 within 

 an old mother cell wall. (Euplanktont). 



Cells 9-13 p. broad, 9-17 /* long. 



Big (rr), Birch (1) (sss), Camp (r), Catfish (r), Devils (1) (rr), Duck 

 (r), Found (rr), Green (2) (rr), Kawaguesaga (rr), Kitten (rrr), Long (2) 

 irr), Mendota (r), North Turtle (r), Pardee (rr), Rock (r), Winnebago (rr). 



OOCYSTIS ELLIPTICA W. West. PI. 22, Fig. 5. 

 Jour. Roy. Micr. Soc. 1892: 736, pi. 10, fig. 56. 1892. 



Cells oblong-elliptic, with poles rounded and without nodules. Chlor- 

 oplasts 10-20, disciform, parietal, without (?) pyrenoids. Cells rarely 

 solitary, generally in families of 48 within an old mother cell wall. 

 ( Tychoplanktont) . 



Cells 11-12.5 /x broad, 20-25 /* long. 



Amicoy (rr). 



