Baker—Molluscan Fauna of Tomahawk Lake , Wisconsin. 207 
MOLLUSCA COLLECTED. 
Planorhis trivolvis. 
Lymnoea lanceata. 
Station V. 
A large bay south of Quynock Point, formed by the raising of 
the level of the lake. A heavy sand bar, formed by wave action, 
encloses the bay. The water on the bar is from a foot to eigh¬ 
teen inches in depth; in the bay it increases to four and five 
feet and outside of the bar on the lake side, it deepens rapidly. 
The entrance to the bay is further closed by a large number of 
logs which form a tangled mass on the sand bar. The rising of 
the water has killed all of the trees formerly occupying the low 
area and the trunks of these dead trees stand in the water. 
The enclosed bay affords an excellent'habitat for a plant so¬ 
ciety consisting of pondweed (Potamogeton), white pond lily 
(Castalia odorata) and yellow pond lily (Nymphoea advena). 
Near the shore a Typha latifolia society is developing. Back 
of the shore the land rises abruptly and is thickly wooded, birch, 
spruce, pine and hemlock being the predominating trees. 
The pond-lily society affords a habitat for Planorhis ibinneyi, 
Physa ancillaria, Lymnoea lanoeata, Amnicola cincirmatiensis 
and Ancylus parallelus. The under side of the lily leaf is 
usually chosen as a resting place, and is doubtless used as a feed¬ 
ing ground also. Musculium securis and Planorhis are plentiful 
in algse, the bay being filed with this plant near the shore. The 
logs are tenanted by Planorhis hinneyi, Physa ancillaria war- 
reniana and Lymnoea lanceata. 
MOLLUSCA COLLECTED. 
Musculium securis. 
Planorhis hirsutus. 
Planorhis himieyi. 
Lymnoea lanceata. 
Ancylus parallelus. 
Physa ancillaria warreniana. { 
Amnicola cincinnatiensis. 
