distinct and not confluent with the colonial mucilage. Pseudociha 

 very fine and 20-30 times the diameter of the cell in length. Chloro- 

 plast a dense parietal plate covering almost the entire wall. Cells 

 9-10.5/A in diameter. 



This species differs from others by the possession of distinct lamel- 

 late cell sheaths and the extraordinarily long pseudocilia. 



Euplanktonic. Wis. 



Tetraspora luhrica (Roth) C. A. Agardh 1824, p. 188 



PL 5, Fig. 9 

 Thallus at first tubular or sac-hke and attached, later becoming 

 laciniate, irregularly expanded and floating, or forming streaming 

 gelatinous strands or skeins when in flowing water. Cells in 4's or, 

 when old, irregularly scattered through the rather firm mucilage; 

 7-10;u, in diameter. 



In ditches, in cold springs, and flowing water; and in the marginal 

 flora of lakes. Mich., Wis. 



APIOCYSTIS NaegeH in Kuetzing 1849, p. 208 



Thallus a pyriform or irregularly bulbous, gelatinous vesicle, at- 

 tached by a narrowed base to submerged aquatic plants and fila- 

 mentous algae. Cells spherical, 64 to hundreds, evenly scattered or 

 sometimes in pairs or in circular zonations within the colonial mu- 

 cilage. Cells bearing a pair of very long pseudocilia. Chloroplast 

 parietal, covering most of the wall; with 1 pyrenoid. 



Underdeveloped stages of this plant can scarcely be differentiated 

 from young or small colonies of Tetraspora. 



Apiocystis Brauniana Naegeli 1849, p. 67 

 PI. 5, Figs. 7, 8, 10 



Thallus an attached, pear-shaped, gelatinous vesicle in which the 

 cells are arranged at the periphery in 2's or 4's. Pseudocilia clearly 

 evident. Cells 6-8ju in diameter. 



Considerable variation in the shape of the vesicle occurs, young 

 colonit being almost round, with a very short stipe, whereas old 

 thalli are oboviform or pyriform. 



This plant is attached to filamentous algae and submerged aqua- 

 tics such as Utricularia. It is common in acid water habitats where 

 temperatures are fairly high and where there is a great deal of 

 organic material. Mich., Wis. 



[89 



