SMITH: ALGAE FROM THE LAKES OF WISCONSIN 481 
Cylindrospermum stagnale angustum var. nov. 
Cells 4.5-4 u wide; 10-8 u long. Heterocysts 6.5~5.5 « wide; 
11-7 ulong. Spores 9-7 wu wide; 25-18 p long. 
PLATE 26, FIG. 24 
DISTRIBUTION: bottom of Oconomowoc Lake. 
The much narrower and shorter spores distinguish this from 
the type. 
Spirulina laxa sp. nov. 
Plant mass dark blue-green. Cells 2.5-2 » wide, in a very loose 
spiral. Width of spiral 6-4 , distance between turns 20-15 y. 
Cell contents blue-green. 
PLATE 26, FIG. 25 
DiIsTRIBUTION: along shore, Soft Lake. 
The loose spiral suggests Arthrospira rather than Spirulina 
but, since a careful examination fails to reveal the presence of 
transverse walls, 1 am convinced the plant in question is a Spirulina. 
Chroococcus limneticus distans var. nov. 
Colonies spherical or ovoid, of four to thirty-two cells, rarely 
more, embedded in a copious, hyaline, unlamellated, gelatinous 
envelope. Cells hemispherical to spherical, with grayish or light 
blue-green contents, ‘‘gas vacuoles” rarely present. 
Diameter of cells 7—-6.5 »; diameter of colonies up to 60 u. 
PLATE 26, FIG. 26 
DIstRIBUTION: plankton, Cranberry and Muskallonge Lakes. 
This Chroococcus variety has the characteristic C. limneticus 
Lemm. structure of a few spherical cells embedded in a wide ge- 
latinous sheath. The cell-dimensions are different from those of 
the other C. limneticus varieties so that it seems best to regard it 
as a new variety. 
Anabaena limnetica sp. nov. 
Trichomes free-swimming, solitary, straight or slightly curved. 
Vegetative cells generally spherical, 10-14 wu in diameter, with 
‘‘gas vacuoles.” Heterocysts spherical, 10-12 in diameter. 
Spores smooth-walled, solitary, ovoid, adjacent to, or a short 
distance from, the heterocysts, 20-17 uw in diameter, 25~20 u long. 
