The Workinrj of the Madison Lakes. 129 



Schultz, C. H. : Die Fortpflanziing uud Ernahrung du Pflauzen, 1838, 

 495. 



Stalher. Report on the Waterville cattle disease (see Arthur). Fourth 

 Rep. Univ. Minnesota, Suppl. 1, Rep. Dep. Agr. St. Paul, 1887, p. 105. 



Thompson: An Alga which colors Bally drain Lake (Ann. Nat. Hist,, 

 1810, 75). 



Treichel: Ueber Polycystis aeruginosa Kiitz, als Ursache von roth 

 gefiirbtem Trinkvasser, (Ber. 2 Versaniml. Westpreuss. Bot. Zool. Vereins 

 zu Marienweider, am 22 Juni 1879. — fide Bor. Jahresber., VII., 1, 486). 



Weisse: Monas Oheini. (Bull. Phys. Math. Acad. St. Petersburg, III., 

 310). 



"VYeisse: Zereite Vei'zeichniss St. Petersb. Infusorien. (Bull. Phys. Math. 

 Acad. St. Petersburg, III., 333). 



Wittrock; Anabaena (DoUchospermum) Nassallii (Kiitz.) Wittr. (Wittroch 

 & Nordstedt's Algae aqa3 dulcis exsiccataj, No. 496; Bot. Notiser, 1882, 58; 

 Bot. Jahresb. X. 1, 330; XI. 1, 244, 280.) 



WoUe: Fresh Water Alga;. Bull. Torr. Bot. Club, VIII., 38; and Fresh 

 Water Algaj of the United States, Bethlehem, 1887. — various places. 



Wood: Contribution to the history of the fresh water algae of North 

 America, p. 39, etc. (Smithsonian Contributions, 1872). 



Zopf : Die Spaltpilze, 1883, 74 et. seg. , where other references concerning 

 Beggiatoa, etc. , are given. 



Description of Plate X. 



1 — 4. Anabaena hassallii (Kg.) Wittr. 



1. Filament of Nosfocflos aquae Lyngb. (X 580). From a sketch kindly 

 furnished by Dr. Boruet. 



2. Filament of Xustoc flos aquae Ag. (X 580). From sketch by Dr. 

 Bornet. 



3. Filament and spore of Anabaena circinalis Rab. (X 580). From trac- 

 ing by Dr. Bornet. from analyses of Algen Sachsens, No. 209. 



4. Fertile filament and two mature spores of Anabaena {aphaerozyga) 

 flos aquae (Lyngb.) (X 580). From Lake Mendota. 



5. Two filaments and mature spore of Anabaena mendotae Ti-elease. 

 (X 580). From Lake Mendota. 



6. Part of filament of Ljjnghija wollei Farlow. (X 580). From Lake 

 Mendota. 



7. Coelosphaerium Kiitzingianum Noeg. From Lake Mendota. — a. 

 Fronds (X 25). b. Group of cells as seen from the surface (X 580). c. Cells 

 as seen in radial section of frond (X 580). 



8. Clathrocystis aeruginosa (Kiittz). From Lake Mendota. — a. Frond 

 (X 25). b. Single ceUs (X 580). 



I 



