44 



PLANKTON OF WINNEBAGO AND GREEN LAKES. 



tained in the various lakes of the state. In addition to what 

 has just been said in comparing the results with those in Green 

 lake and Lake Winnebago, something should be said of the lakes 

 as compared with each other. The collections on the northern 

 lakes were made in the course of four rapid trips in four suc- 

 cessive years. The collections of 1899 were made in the latter 

 part of September, and those of the succeeding years about the 

 middle of August. The collections were practically synchro- 

 nous in each year, and a comparison of the figures is interesting, 

 although, as I have said in another part of this paper, one must 

 be careful about drawing inferences from a small number of 

 collections, and it is only averages upon which one can place 

 much reliance. 



In the following table, in which I have listed the lakes of 

 this circuit for the sake of comparison, I have placed first Birch 

 and Stone lakes which belong distinctly to the class of small 

 deep lakes, next Sand lake, which is intermediate between the 

 two classes, then the Clover Leaf lakes, which, although shal- 

 low, yet because of their small size, have a marked thermocline; 

 the rest of the list belong distinctly to the shallow lake type. As 

 the Eagle River lakes do not differ materially in the amount of 

 their plankton, I have listed only one, the largest, Eagle lake. 



