117] FAUNA OF BIG VERMILION RIVER—BAKER 19 
fauna of the Big Vermilion necessary. As a large mussel fauna lives in the 
stream it follows as a corollary that there must also be a fish fauna of com- 
parable size. Fortunately, Dr. S. A. Forbes, caused extensive collections 
to be made in 1901, and these are listed on the maps accompanying the 
work on the Fishes of Illinois, by Forbes and Richardson (1908). Fifty 
species are recorded from the Big Vermilion River and its tributaries (see 
Table II). It will be seen that at this date 28 species were found below 
Urbana, in that portion of the stream now heavily polluted. 
Between the years 1908 and 1912, the Salt Fork between Urbana and 
St. Joseph was deepened and straightened and the bottom fauna was com- 
pletely destroyed. In the canal thus formed, for the purpose of carrying 
off the sewage of the Twin-Cities, no living clams, crayfish, or other clean 
water animals have been found, and but one school of young fish (bull- 
heads) was observed during several examinations of this part of the stream. 
It is possible that during periods of high water in the spring, some hardy 
fish may venture into this heavily polluted area. Below St. Joseph it is 
quite probable that some fish are found during high water periods. A 
few minnows were observed near the station called bench mark 655, about 
fifteen miles below Urbana. A farm boy reported that bullheads could be 
caught at high water on set lines. 
Below bench mark 655, and for some distance above it, fish must resort 
in some numbers because of the presence of a fair sized mussel fauna (see 
Table III). Young mussels, however, were not seen in any number above 
the Homer Park dam, and it is possible that the upper stream is now little 
visited by fish suitable for glochidial infection. Below the dam, young 
mussels are plentiful at all points examined. 
Information concerning the species of fish that carry glochidia of the 
river mussels is still of a fragmentary character. Suber (1912), Howard 
(1914), and other workers of the U. S. Bureau of Fisheries have published 
considerable data on this subject, but much more is needed before one 
can fully understand the relation between mussels and fish. 
Three species of mussels living in Salt Fork and other parts of the 
Big Vermilion River are known to have glochidia encysted on five species 
of fish, all of which have been reported from the Big Vermilion, viz.: 
Mussels Fish 
Lampsilis anodontoides Lepomis humilis 
“« anodontotdes Pomoxis sparoides 
“ ~ anodontoides ‘ annularis 
Quadrula metanevra Lepomis pallidus 
“ pustulosa Pomoxis annularis 
« pustulosa Ictalurus punctatus 
