or 4; chloroplast massive and parietal with 1 pyrenoid; cells 14-16ju, 

 in diameter, 16-19ft long; colony of 4 cells up to 36/a in diameter, 

 48.8/i long. 



This species should be compared with O. apiculata W. West, a 

 much smaller plant with broadly elliptic cells. 

 Plankter; in a cedar swamp. Wis. 



Oocystis solitaria Wittrock in Wittrock & Nordstedt 1879, p. 24 



PI. 54, Fig. 10 



Often solitary, or in a family of 2-8 cells inclosed by the old 

 mother cell wall; cells ovate or ellipsoid; poles with nodular 

 thickenings; chloroplasts numerous parietal plates, each with a 

 pyrenoid; cells 3-9/^ in diameter, 7-20/x long. 



Common in the euplankton of lakes; also in tychoplankton among 

 filamentous algae. Mich., Wis. 



Oocystis solitaria var. mapr Wille 1879, p. 26 



A form differing from the typical by having sharply pointed poles 

 and by its larger size, about IG.S^u, in diameter, 29/a long. 

 Rare; in plankton. Wis. 



Oocystis siibtnarina Lagerheim 1886, p. 45 



PI. 54, Fig. 12 



Usually a family of 2-16 oblong-cylindrical cells, rarely solitary; 



cells narrowed at the poles and furnished with a nodular thickening; 



chloroplasts 1-3 parietal plates with 1 pyrenoid each; cells 3-9/x 



in diameter, 7-20;a long. 



Rare; in eu- and tychoplankton. Mich., Wis. 



GLOEOTAENIUM Hansgirg 1890, p. 10 



A free-Hoating, spherical or quadrangular-ovate colony of 2-8 

 globose or ellipsoid cells compactly and cruciately arranged within 

 the persistent mother cell wall; cells separated within the colony 

 by dark-colored masses of mucilage containing calcium carbonate, 

 usually appearing as 2 X-shaped bands and sometimes almost 

 entirely masking the inclosed cells, a cap of dark mucilage also 

 appearing between the cells and the colonial membrane; chloroplast 

 massive and indeterminate in shape. 



There is but 1 species in this genus; it is rather rare and widely 

 distributed. 



[247] 



