30 
Charles K. Biernbaum 
Thorp, James H., and E. A. Bergey. 1981. Field experiments on responses of a 
freshwater, benthic macroinvertebrate community to vertebrate predators. 
Ecology 62(2):365-375. 
Vigerstad, T. J., and L. J. Tilly. 1977. Hyperthermal effluent effects on 
heleoplanktonic Cladocera and the influence of submerged macrophytes. 
Hydrobiologia 55( 1 ): 8 1 -85. 
Williams, W. D. 1970. A revision of North American epigean species of 
Asellus ( Crustacea: Isopoda). Smithson. Contrib. Zool. 49:1-80. 
Williams, W. D. 1972. Freshwater Isopods (Asellidae) of North America. Biota 
of Freshwater Ecosystems, Identification Manual No. 7. U.S. Environ. 
Prot. Agcy., Washington, D.C. 
Accepted 14 November 1986 
ADDENDUM 
In June 1986, two specimensbelonging to an undescribed amphipod 
species in the genus Gammarus were collected from the sandy bottom 
of Lake Marion adjoining Cuddo unit. This species belongs in the G. 
fasciatus-tigrinus complex that, according to Fox (1978), includes two 
or three undescribed species from South Carolina to Louisiana. 
