84 ILLINOIS BIOLOGICAL MONOGRAPHS [182 
green putrescent matter, measuring in size from a peanut to a dish pan. 
Some of these masses are brownish, where the algae and Protozoa have not 
completely taken possession of them. 
A large amount of oily scum may be observed on the surface and 
when disturbed the bottom emits quantities of oily matter, as is the case 
higher up the stream. On exposed bars and along shore the algae and 
putrescent matter have dried and caked, forming a pavement-like layer. 
The water is clearer here than in the portion of the stream previously 
examined, but no clean water life could be found; mussels, crayfish, and 
insects were entirely absent. 
Samples of the bottom from the stream about 300 feet east of the 
Mayview road bridge, about six miles below the Champaign outlet were 
examined. The following life was present: 
Blue-green algae Animals 
Pediastrum simplex, rare. Ciliata, minute, abundant. 
Phormidium inundatum, common. Colpodium, several. 
Diatoms Euglena geniculata, very abundant. 
Navicula salinarum, abundant. Limnodrilus, common. 
Fragilaria capucina, abundant. Nematode worms, minute, abundant. 
About a mile and a half below this locality additional samples were 
taken for examination. Conditions are similar but the water is not as 
clear, holding more sediment in suspension. 
Blue-green algae Animals 
Pediastrum simplex, rare. Ciliata, minute, abundant. 
Phormidium inundatum, abundant. Paramoecium, several. 
Diatoms Euglena geniculata, abundant. 
Fragilaria capucina, abundant. Limnodrilus, about a dozen. 
Nematode worms, minute, many. 
At the last north and south farmer’s bridge, the canal makes a wide 
sweep, in a southeasterly direction (Fig. 43) leaving the old stream bed 
to the west of the new channel, in the form of an ‘ox-bow’ almost half 
a mile in length, which, during the greater part of the year, forms a large 
elongated pond, that drains into Salt Fork canal by means of a small outlet 
at the south end which turns abruptly northeastward as it empties into the 
canal. At the time examined, the bed of this old stream was almost dry, 
following a period of very dry weather, and the fauna had retired to several 
small, shallow, muddy pools which remained in the deeper parts of the 
stream bed. An examination of these pools disclosed a number of bull- 
heads (Ameiurus melas), many dragonfly larvae (Libellula pulchella), 
and a few mollusks (Planorbis trivolvis, Physa gyrina, and Musculium 
transversum). 
