216 Wisconsin Academy of Sciences, Arts, and Letters. 
varies in extent from a few feet to a quarter of a mile in width, 
in the latter case a marsh being formed. The banks of the river 
are lined with heavy thickets with here and there a forest growth 
of maple, birch, etc., extending to the water. Several species 
of swamp grass occupy the flood plain, and Iris and Typha 
societies are scattered over the area, in the vicinity of pools. 
The river has a very swift current, forming an ideal environ¬ 
ment for naiads, a number of species of which live in this hab¬ 
itat. The larger and heavier mussels live in deep water, but 
Lampsilis luteola, together with Sphcerium and Campeloma, 
seem to prefer the shallows near the shore. Campeloma was 
also plentifully distributed over the surface of floating logs. 
Lymncea humilis modicella was observed to cover the exposed 
mud flats along the edge of the water. 
Station I. 
Deep Water of Wisconsin River. 
Lampsilis ligamentina. 
Lampsilis recta. 
Lampsilis ventricosa. 
Quadrula undulata. 
Substation 2. 
Shallow Water Along Shore of River. 
Lampsilis luteola. 
Sphcerium striatinum. 
Pisidium virginicum. 
Campeloma decisum . 
Substation 3. 
Muddy Flats Above High Water. 
Lymncea humilis modicella. 
Succinea retusa. 
