561 
sis, production in Phelps and Flag lakes exceeds that reported 
in any other body of water save only from the shoaler part of 
Turkey Lake (Juday, 97). This greater production in Turkey 
Lake disappears if centrifuge measurements are employed in both 
planktons, the ratios being 203.52 and 224.48 em.‘ for Flag and 
Phelps lakes to 136.8 and 27.1 em.‘ for Turkey Lake. The ten- 
dency on the part of this maximum production in all of the lo- 
ealities to fall in either the April-May period or in that of 
August-September is apparent, though in some cases, as, for 
example, those of Lakes Michigan and St.Clair, and Turkey 
Lake, the limitation of collections to a few weeks in midsum- 
mer precludes the possibility of a vernal pulse appearing in 
their records. 
