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College of Forestry 
4. Species on submerged portion of Bulrushes (Scurpus). 
Lymnea stagnalis lillian, rare on 
S. amer.canus. 
Planorbis campanulatus, common 
on S. americanus and S. occiden- 
talis. 
Planorbis antrosus, 
on S. occidentalis. 
Planorbis trivolvis, var., common 
on S. americanus and S. occiden- 
talis. 
not common 
Physa ancillaria warreniana, €om- 
mon on S. americanus. 
Galba catascopium, common on 8. 
americanus and 8. occidentalis. 
Bythinia tentaculata, not common 
on S. americanus and S. occiden- 
talis. 
Acella haldemani, common on 8. 
smith. 
Acella adheres so closely to the leaf of the Bulrush that it 
resembles a sharp spine protruding from the plant. 
Fig. 38. 
. Lymnea stagnalis lilliane (2). 
. Planorbis trivolvis (10). 
. Planorbis exacuous (2). 
wre 
Diagram illustrating quantity of mollusks in one square foot 
at station XXXI, habitat 2. 
leaves in and on water. 
A Typha marsh with dead 
29 specimens present. 
4. Planorbis parvus (3). 
5. Ancylus fuscus (12). 
