[Vor. 4 
300 ANNALS OF THE MISSOURI BOTANICAL GARDEN 
Genus NEPHROCYTIUM Naegeli 
Nephrocytium Naegelii Grunow in Rabenhorst, Fl. Eur. 
Alg., Sect. 3:52. 1868. Occurring rather frequently in 
towings. 
Genus оосүвтів Naegeli in A. Braun 
Oocystis solitaria Wittrock in Wittr. & Nordst. Alg. Exsice. 
No. 244. Cells slightly larger than given for this species but 
not approaching forma major, otherwise typical. Frequently 
found in towings from various parts of the lake. 
Genus SCENEDESMUS Meyen 
Scenedesmus bijuga (Turp.) Kuetzing, Syn. Diat. 607. 1834. 
Scenedesmus quadricauda (Turp.) Brébisson forma typicus 
Kirchner in Cohn’s Kryptogamenfl. von Schlesien, 98. 1878. 
Both species rather common in towings, also associated 
with filamentous algae along shore. 
Genus ZOOCHLORELLA Brandt 
Zoochlorella conductrix Brandt, Archiv f. Physiol. 18821; 
140. 1882. In Stentor from towings. 
Family HYDRODICTYACEAE 
Genus PEDIASTRUM Meyen 
Pediastrum angulosum (Ehrenb.) Meneghini, Linnaea 14: 
211. 1840. 
Pediastrum Boryanum (Turp.) Meneghini, Linnaea 14: 
210. 1840. 
Both species rather frequent in towings. 
Order ULOTRICHALES 
Family UrorRiCHACEAE 
Genus microspora Thuret 
Microspora Loefgrenii (Nordst.) Lagerheim, Ber. d. deut. 
bot. Ges. 5: 417. 1887. With Tolypothrix and other fila- 
mentous forms along shore. Agrees well with the species ex- 
cept that occasionally the wall may be up to 6 y thick. 
