185] FAUNA OF BIG VERMILION RIVER— BAKER 87 



were found, in more or less abundance, and insects were also abundant. 

 The water is low, two or three feet deep in the channel in the fall and the 

 bottom is very muddy. A very small amount of green algae was noted 

 on the surface, evidently brought up from Salt Fork. The mussels col- 

 lected included: 



Lasmigona complanata Lampsilis luteola 



Amblema undulata Eurynia lienosa 



Carunculina parva 



A water boatman (Corixa, near burmeisteri) was very abundant, 

 especially in the nymph stage, as were also numerous gyrinid beetles 

 (Dineutes assimilis). Though the water was low, men were observed 

 fishing for bullheads in this part of Spoon River. The contrast between 

 this stream, with its abundance of clean water life, and the adjacent parts 

 of Salt Fork, which is utterly devoid of clean water life, strikingly indicates 

 the harmful efifects of sewage pollution on the fauna of our streams. 



Samples of the green matter floating on the water of the Spoon River 

 were examined and found to contain Euglena geniculata, common, ciliate 

 Protozoa, many. These masses seem to be made up almost entirely of 

 these animals and low plants, of which three species were noted: Phormi- 

 dium inundatum alga; Navicula salinarum and Fragilaria capucina, dia- 

 toms. A single pupa of Chironomus decorus was found at this place. 



For a distance of several miles below St. Joseph unfavorable conditions 

 seem to prevail, no living mussels being found for a distance of over four 

 miles, and here they occur rarely. Living mussels are not found in any 

 number for a distance of over five miles below St. Joseph. These animals 

 are not abundant in species and individuals until a distance of twenty miles 

 has been traversed below Urbana. Conditions for a distance of two miles 

 below St. Joseph are similar to those described for the area just below 

 Spoon River, the bottom consisting of black mud from which bubbles of 

 ill-smelling gas rise when the bottom is disturbed. Below this point condi- 

 tions begin to improve, though very gradually. 



That conditions along the polluted portion of Salt Fork are often, if not 

 always, highly objectionable was evidenced from conversations with far- 

 mers living near the stream. One farmer, who had built a small house 

 within a few hundred feet of the stream, stated that the "stench was at 

 times almost unbearable" and that people living half a mile away were 

 strongly conscious of the odor. This was about five miles down the 

 stream from Urbana. A gentleman driving along the road which parallels 

 the Salt Fork east of Cottonwoods road, stated that the odor on Septem- 

 ber 10 was very obnoxious. People living a mile south and north of the 

 stream do not suffer from these odors. 



