Gammarus Variability 
147 
Holsinger, John R. 1976. The freshwater amphipod crustaceans (Gammaridae) 
of North America. Biota of Freshwater Ecosystems. Ident. Man. 5, U.S. 
Environ. Protect. Agency, Washington. 89 pp. 
, and D. Culver. 1970. Morphological variation in Gammarus minus 
(Amphipoda, Gammaridae) with emphasis on subterranean forms. Postilla 
746:1-24. 
Hubricht, Leslie. 1943. Studies on the Nearctic freshwater amphipoda, III. Notes 
on the freshwater Amphipoda of the eastern United States, with descrip- 
tions of ten new species. Am. Midi. Nat. 29:683-712. 
Minckley, W.L., and G.A. Cole. 1963. Ecological and morphological studies on 
gammarid amphipods {Gammarus sp.) in spring-fed streams of northern 
Kentucky. Occasj Pap. Adams Cent. Ecol. Stud. West. Mich. Univ. 70:1-35. 
Pinkster, S. 1971. Members of the Gammarus pulex group (Crustacea- 
Amphipoda) from North Africa and Spain, with description of a new 
species from Morocco. Bull. Zool. Mus. Univ. Amst. 2:45-61. 
1972. On members of the Gammarus pulex group (Crustacea - 
Amphipoda) from western Europe. Bijdr. Dierk. 42:164-191. 
Shoemaker, Clarence R. 1940. Notes on the amphipod Gammarus minus Say and 
description of a new variety, Gammarus minus var. tenuipes. J. Wash. Acad. 
Sci. 50:388-394. 
Accepted 3 May 1980 
