been eliminated from this pool than from other parts of the river (Star- 

 rett, 1971: 356). 



A comparison of species records for pre-dam (1930) and post-dam (1955) 

 years indicates the loss of 3 species from the river in the vicinity of 

 Meredosia (Table 6 ). Specifically, the yellow sand-shell (_L. anodontoides ) 

 liliput shell (C . parva ) , and the paper pond-shell (A. imbecillis ) were 

 present in 1930 but absent in 1955. Paper pond-shells were, however, 

 collected below Meredosia (Naples — river mile 65.5) in 1966 (Starrett, 

 1971: 356). 



While the liliput shell and paper pond-shell are not of commercial 

 value, the yellow sand-shell was an important commercial species. 

 Danglade (1914: 45) in discussing the yellow sand-shell in the Illinois 

 River (1912) stated: 



This species is found sparingly throughout the upper river, 

 but is fairly abundant in the Hardin district, where it 

 is in sufficient quantity to be sorted out and sold separately 

 at an advanced price. This shell is the most valuable of '. 

 the freshwater mussels . . . 



The yellow sand-shell may still occur in Alton Pool as a rare species 

 (Starrett, 1971: 357). 



While the fat mucket (L. luteola ) and fawn's foot (T. donaciformis ) 

 were found near Meredosia in 1955, they were not found there in 1966 

 (Table 6 ) . A single specimen of the fat mucket was found in a commer- 

 cial shell pile at Meredosia in 1966 and Starrett believed this species 

 would soon be eliminated from the river (Starrett, 1971: 336). While 

 the fawn's foot was not collected from Alton Pool by Starrett in 1966, 

 it probably occurred there in small numbers (Starrett, 1971: 327). 



As late as 1966 only the Alton Pool of the Illinois River supported 

 relatively large populations of pimple-backs (Q. pustulosa ) and wash- 

 boards (M. gigantea ) and moderate populations of warty-backs (Q. nodulata ) 

 and three-horned warty-backs (Q. reflexa ) (Starrett, 1971: 356). The 

 predominant species taken by mussel fishermen from the Illinois River in 

 the 1960 's were the three-ridge (A. plicata ) and washboard (M. gigantea ) 

 (Lopinot, 1968: 8). 



38 



