Rhabdoderma Gorskii Woloszynska 1918, p. 127 

 PI. 103, Fig. 4 

 A fusiform colony with uneven margins; cells cylindrical, 7-10 

 times their diameter in length, arcuate or somewhat sigmoid, the 

 poles broadly rounded, loosely scattered with their longitudinal 

 axes approximately parallel with that of the colony, indosed in a 

 wide, hyaline, mucilaginous envelope; cell contents bright blue- 

 green, homogeneous; cells 1.5-2/^ in diameter, 10-14/x long. 

 Euplankter; in soft water lakes. Wis. 



Rhabdoderma irregulare (Naumann) Geitler 1925a, p. 113 



PI. 103, Figs. 9, 10 

 An ovate colony of sigmoid, cylindrical cells irregularly arranged 

 within a copious, gelatinous envelope; cells 1.5-2^ in diameter, 

 4.5-5-(6)/xlong. 



Euplankter; in semi-hard water lakes. Wis. 



RJiabdoderma lineare Schmidle & Lauterborn in 

 Schmidle 1900e, pp. 148, 149 

 PI. 103, Figs. 11, 12 

 A fusiform colony of cylindrical, nearly straight cells arranged 

 with their longitudinal axes parallel with that of the colony, some- 

 times several cells end to end in a series; colonial envelope trans- 

 parent and wide; cells 1.8-2.0/x in diameter, 8-10/a long; cell contents 

 blue-green, homogeneous. 



Uncommon in the euplankton of several soft water and acid 

 lakes. Wis. 



Rhabdoderma sigmoidea fa. minor Moore & Carter 1923, p. 398 



PI. 103, Figs. 5, 6 



Cells arcuate and much twisted, sigmoid and lunate, irregularly 

 arranged in a hyaline envelope; cell contents pale blue-green; cells 

 1.5-1.6]u, in diameter, 15-1 6/x long. 



The much twisted and contorted shape of the cells is a constant 

 character; cells more slender than in the typical plant. 



Euplankter. Wis. 



DACTYLOCOCCOPSIS (Reinsch) Hansgirg 1888b, p. 590 

 Cells fusiform, solitary or colonial, of various shapes, straight, 

 sigmoid, arcuate, or spirally twisted; when colonial usually inclosed 

 by a fusiform gelatinous envelope, the individual cell sheaths in- 



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