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part of May would be far more enlightening than any descrip- 

 tion that might be given. As we leave the sandy shore of 

 Quiver we traverse the clear, cold, and spring-fed water along 

 the eastern bank with its rapidly growing carpet of Cerato- 

 phijllum, and in a few rods note the increasing turbidity, rising 

 temperature, and richer plankton of the water which has moved 

 down from the more or less open and slightly submerged 

 bottom to the north (PI. II.). As we cross the muddy bank of 

 Quiver ridge and enter the main channel of the river we find 

 rougher water, caused by the wind which usually sweeps up or 

 down the stream with considerable force between the bordering 

 forests. The water also appears much more turbid by reason 

 of silt and plankton, and no trace of vegetation is to be seen 

 save occasional masses of floating Ceratophyllum or isolated 

 plants of Lemna, Wolffia, or Spirodela. Huge masses of cattle- 

 yard refuse, veritable floating-gardens, may also at times be 

 seen moving down the channel or stranded in some eddy along 

 shore. As we plunge into the willow thicket on the western 

 shore we have to pick our way through the accumulated drift 

 lodged in the shoals or caught by the trunks of the trees or the 

 submerged underbrush. The surface of the water is one mat 

 of logs, brush, sticks, bark, and fragments of floating vegeta- 

 tion, with its interstices filled with Lemnacece dotted with the 

 black statoblasts of Plumatella. From this dark labyrinth we 

 emerge to the muddy but quiet waters of Seeb's Lake with its 

 treacherous bottom of soft black ooze. We next enter a wider 

 stretch of more open territory with scattered willows and ma- 

 ples and a rank growth of semiaquatic vegetation, principally 

 Polygonums. The water is clearer and of a brownish tinge 

 (from the diatoms), while mats of algse adhere to the leaves 

 and stems of the emerging plants. A flock of startled water- 

 fowl leave their feeding grounds as we pass into the wide ex- 

 panse of Flag Lake. We push our way through patches of lily- 

 pads and beds of lotus, past the submerged domes of muskrat 

 houses built of last year's rushes, and thread our way, through 

 devious channels, among the fresh green flags and rushes just 



