80 ILLINOIS ACADEMY OF SCIENCE 



lacustre in the pond southeast of Lerna, May, 1912. 

 Lerna, May, 1912. 



Scenedesmaceae 



Zoochlorella conductrix Brandt. 



Occurs abundantly associated with the green Hydra and 

 Paramoecium bursaria. 

 Zoochlorella parasitica Brandt. 



Found in the west Big Four pond, Charleston, in the 

 fresh water sponge. 

 Raphidium falcatum (Corda) Cooke. 



x\ common constituent of the pond plankton. 

 Oocystis solitaria, forma major Wille. 



Common in the ice plant pond at Casey. 

 Gloeotaenium Loitlesbergerianum Hansgirg. 



Has been collected in Hodgen's pond, the middle Tile 

 Factory pond, and the east Big Four pond, near Char- 

 leston. Occurs from June to October. Consists of 

 single cells and 2-, 4- and 8-celled families. The life 

 history of this peculiar form has been described in the 

 Botanical Gazette. Jan.. 1913. 

 Nephrocytium Agiardhianum Naegeli. 



Common in all of the more permanent ponds. 

 Scenedesmus bijuga (Turp.) Wittrock. 



Very common in the plankton of ponds. This and the fol- 

 lowing species multiply rapidly in laboratory aquaria 

 and color the water a 1)right green. Species of Rha- 

 phidium are commonly associated with them. 

 Senedesmae bijuga alternans (Reinsch) Hansgirg. 



Occurs with the type. 

 Scenedesmus obliquus (Turp.) Kuetzing. 



Found in plankton from the Lily pond on the campus. 

 Scenedesmus quadricauda (Turp.) Kuetzing. 



Very common. Along with the type I have noted the 

 forms setosus, abundans, and horridus of Kirchner. 

 Crucigena rectangularis (A. Braun) Gay. 



Abundant in the east Big Four pond during September, 

 1911. 

 Selenastrum acuminatum Lagerheim. 



Not infrequent in plankton from ponds. 

 Kirchneriella lunaris (Kirchner) ]\Ioebius, 



\^ery rare. 

 Coelastrum cambricum Archer. 



Seen in material from the Lily pond on the Campus, 

 and the pond at Urban Park, Charleston. 

 Coelastrum microporum Naegeli. 



Very abundant in most of our ponds. 



