46 WISCONSIN PHYTOPLANKTON 



lated, sometimes 2-8 cells enclosed by a single sheath. Cells elongate 

 to broadly cylindrical, with rounded ends and irregularly distributed 

 throughout the colonial envelope or with their longer axes pointing in 

 the same general direction. Cell contents homogeneous or finely granu- 

 lose; grey, pale to bright blue-green, or olive green in color. 



Eeproduction by vegetative division of cells at right angles to their 

 long axes. 





G-LOEOTHECE LiNEARis Nageli. PI. 6, Fig. 5. 

 Gatt. einz. Algen 58, pi. 1, fig. G 2 . 1849. 



Colonies small; dull yellow to flesh color or dirty olive-green; en- 

 closed by a broad, hyaline, homogeneous, gelatinous envelope. Cells 

 elongate-cylindrical, straight or arcuate, with rounded ends. Sheaths 

 containing one cell only, broad, hyaline, having the same general out- 

 line as the cell. Cell contents homogeneous ; pale to bright blue-green. 

 (Tychoplanktont) . 



Cells (without sheath) 1.3-2.5 p. broad, 10.5-18 p. long; (with sheath) 

 4-6 p. broad, 13-22 p. long. 



Harris (r), Muskallonge (rr). 



var. composita var. nov. PI. 6, Fig. 6. 



Cells shorter and 2-8 enclosed by a single, broad, firm, homogeneous 

 sheath. Individual sheaths of single cells or groups of cells not con- 

 fluent with the colonial envelope. (Tychoplanktont). 



Cells (without sheath) 3.0-3.5 p. broad, 4-8 p. long; sheaths 10-12 

 p. broad, 20-35 /*. long. 



Deer (rrr). 



RHABDODERMA Schmidle and Lauterborn. 1900. 



Colonies free-floating, small, of comparatively few cells enclosed by a 

 hyaline, homogeneous, gelatinous envelope. Cells cylindrical, witk 

 rounded apices, straight or arcuate; with their long axes pointing in 

 the same general direction. Individual sheaths of cells confluent with 

 colonial envelope. Cell contents homogeneous; grey to bright blue- 

 green in color. 



Reproduction by vegetative division of cells, the divisions taking 

 place at right angles to the long axes of the cells. 



