30 WISCONSIN PHYTOPLANKTON 



Diam. cells (without sheath) 3.5-4.5 /*; (with sheath) 4.5-5.5 /t. 



Big Bass (sss), Blake (rr), Lac Court Oreilles (ss), Owen (ss), Paddock (r). 



The chief distinction of this and the following varieties is in the size 

 of the cells. 



var. CAKNEUS (Chodat) Lemmermann. PI. 1, Fig. 6. 

 Arkiv for Botanik 2, No. 2: 101. 1904. 



Cells spherical to hemispherical, 4-8-16 irregularly distributed 

 throughout a spherical to ovoid gelatinous matrix. Individual sheaths 

 of cells confluent with the colonial envelope. Cell contents homogene- 

 ous; color variable, ochraceous, grey, blue-green or olive green. (Eu- 

 planktont) . 



Diam. cells (without sheath) 7-9 p.. 



Big Bass (ss), Harris (r), Mendota (rr), Nancy (r), Oconomowoc (rr). 



var. DISTANS G. M. Smith. PI. 1, Fig. 7. 

 Bull. Torr. Bot. Cl. 43: 481, pi. 26, fig. 26. 1916. 



Cells spherical to hemispherical, 8-32 in a colony and lying some 

 distance from one another within a spherical to ovoid, hyaline, homo- 

 geneous, gelatinous, colonial envelope. Individual cell sheaths con- 

 fluent with the colonial envelope. Cell contents homogeneous, grey to 

 pale blue-green in color. (Euplanktont). 



Diam. cells (without sheath) 6.5-7 /*. 



Bear Trap (s), Birch Island (rr), Browns (sss), Cochrane (r), Cranberry 

 (sss), Lindy (rr), Muskallonge (rr). 



var. ELEGANS G. M. Smith. PI. 1, Fig. 8. 

 Trans. Wis. Acad. Sci., Arts, & Lett. 19 1 : 619. 1918. 



Cells circular to semicircular in front view, somewhat flattened in 

 side view. Colonies enclosed by a spherical, homogeneous, hyaline, gel- 

 atinous envelope. Individual sheaths of cells conspicuous. Cell con- 

 tents homogeneous; generally bright blue-green in color. (Euplank- 

 tont) . 



Diam. cells (without sheath) 18-22 /*; (with sheath) 20-26 fi. 



Delavan (rr). 



CHROOCOCCUS GIGANTEUS W. West. PI. 2, Fig. 1. 

 Jour. Roy. Micr. Soc. 1892: 741, pi. 10, figs. 59-60. 1892. 



Cells ordinarily hemispherical, rarely becoming spherical or ovoid 

 after division. Solitary or in colonies of two (rarely 3-4) enclosed by 



