Figure Page 



13. Seasonal distribution of diatomfi, greens and blue-greens in 



the Island Section, 1929 l5l 



lU. Seasonal distribution of diatoms, greens, and blue-greens in 



the Island Section, 1930 l53 



15. Comparison of seasonal distribution of diatoms in 1929 and 



1930 l61i 



16. Comparison of seasonal distribution of greens in 1929 and 



1930 167 



17. Comparison of seasonal distribution of blue-greens in 1929 



and 1930 170 



18. Average abundance of phytoplankton groups, and of albuminoid 



and free ammonia, in the Maumee Bay Section in July, 



Augus t and September 1930 190 



19. Seasonal distribution of plankton Crustacea in the Island 



Section, 1929 ?17 



20. Seasonal distribution of plankton Crustacea in the Island 



Section, 1930 221 



21. Comparison of the seasonal distribution of Crustacea in 1929 



and 1930 22I; 



22. Ab\indance of Tubificidae and Hexagenia at 11 stations along 



a line from, the mouth of Maumee River to a point 20 miles 



out in the lake 276 



23. Sampling stations and zones of pollution of the botton in 



west part of Western Lake Erie 280 



