Unionid Mollusks 
83 
Fig. 23-31. Pleurobemini (Unioninae), localities in parentheses. 23, Elliptio 
folliculata (16). 24-25, E. icterina (both 24). 26-31, Uniomerus tetralasmus: 26-28 
(17), 29 (8), 30 (18), 31 (21). Scale line = 10 cm. 
encountered in the Neuse River between Raleigh and Lenoir County, a 
reduction in diversity that he attributed to pollution. As expected, E. 
complanata is widespread in the upper Cape Fear, and was collected at 
24 stations. Elliptio complanata is a highly variable species and subject 
to extreme ecophenotypic variation, which has generated the large 
number of synonyms. Seven forms are shown in Figures 32 through 38. 
The species can be easily confused with other representatives of the gen- 
era Elliptio and Uniomerus, and close attention should be paid to the 
illustrations here, in Johnson (1970), and in Burch (1975) when making 
determinations. 
