181] 



FAUNA OF BIG VERMILION RIVER— BAKER 



83 



Collections of materials made just below the third farmer's bridge, about 

 three and a half miles below the Champaign outlet, contained the following 

 organisms: 



Blue-green algae Animals 



Phormidium inundatum, abundant. Flagellate Protozoa, very minute. 



Diatoms Euglena geniculala, very abundant. 



Navicula salinarum, abundant. Many in stage of encystment. 



Dineutes assimilis, very abundant. 



On the surface of the water. 



Collections at the Cottonwoods bridge (Fig. 42) contained a larger 

 variety of animal life, which was rather meagerly represented above 

 this bridge. This place is on the east line of section 11, about four miles 

 below the Champaign outlet. The bottom here is of fine sand and mud. 



Blue-green algae 



Phormidium inundatum, abundant. 



Diatoms 

 Navicula salinarum, abundant. 



Animals 



Euglena geniculala, very abundant. 

 Rotifer, illoricate, one specimen. 

 Limnodrilus, two specimens. 

 Dineutes assimilis, a few examples. 



Mussel shells or other mollusks were entirely absent in a living state 

 and their shells were notably rare. About three quarters of a mile below 

 the first bridge east of Urbana, a half valve of Lampsilis luteola was found 

 on a sand bar (Fig. 37). Near the Brownfield woods bridge many broken 

 pieces of mussel shells, as well as a few mutilated half valves, were ob- 

 served. At a farmer's bridge half a mile below this bridge several broken 

 valves of Lampsilis luteola and Anodonta grandis were collected, (Fig. 

 38) and from this point down stream to the Cottonwoods road bridge 

 detached valves or broken pieces of shell wer€ more or less common. 

 From observations of this and other parts of the stream it seems evident 

 that these mutilated shells were washed from the spoil banks on either side 

 or from the bed of the old stream channel where it crosses the canal. At the 

 junction of the Boneyard with the Salt Fork a layer of these shells was 

 observed in the bank, about eighteen inches above the water line (the water 

 being low), in a position that indicated the old bed of the Salt Fork before 

 the canal was excavated. High water would wash this material way and 

 provide the odd valves of mussels observed in different parts of this stream. 



Below Mayview road bridge the conditions are much the same as in 

 the neighborhood of the Cottonwoods bridge. The bottom is of sand and 

 gravel, with some mud bordering the shore. The water is from a few 

 inches to a foot in depth, the channel meandering among a continuous 

 series of sand bars. The sand is ripple-marked in places and streaked 

 with bands of dark green algae, with yellowish algae in spots. The surface 

 of the flowing portion of the stream is thickly covered with patches of dark 



