Silverberg, B.A. 1975. UUrastructural localization of lead in Stigeo - 

 clonium tenue (Chlorophyceae, Ulotrichales) as demonstrated by cyto- 

 chemical and x-ray microanalysis. Phycologia. 14: 265-274. 



Silverberg, B.A. 1976. Cadmium-induced ultrastructural changes in mito- 

 chondria of freshwater green algae. Phycologia. 15: 155-159. 



Smith, V.E., K.W. Lee, J.C. Filkins, K.W. Hartwell, K.R. Rygwelski and J.M. 

 Townsend. 1977. Survey of chemical factors in Saginaw Bay (Lake 

 Huron). Ecol. Res. Series, U.S. Environmental Protection Agency, 

 Duluth, MN, Rep. No. EPA-600/3-77-125. 143 p. 



Stempak, J.F. and R.T. Ward. 1964. An improved staining method for elec- 

 tron microscopy. J. Cell Biol. 22: 697-701. 



Stoermer, E.F. and R.G. Kreis, Jr. In press. Phytoplankton composition and 

 abundance in southern Lake Huron. Univ. Michigan, Great Lakes Res. 

 Div., Spec. Rep. No. 65. 382 p. 



186 



