Baker—Molluscan Fauna of Tomahawk Lake, Wisconsin. 201 
An ecological study of the Mollusca entails not only a consider¬ 
ation of the mollusks themselves, but also of those animals and 
plants intimately associated with them, and the ecological study 
of any one group naturally includes, if exhaustively carried on, 
a fairly complete discussion of the biota of the area under con¬ 
sideration. Time and means, however, did not permit of an ex¬ 
haustive study of the entire biota, and only a few animals, as 
well as some typical plants, were collected and noted. 
My thanks are due the following persons: Mrs. Frank C. 
Baker, of Chicago; Mrs. Harry L. Burke, of Kansas City; Mr. 
Don Blanchard, of Chicago, and Mr. Claude Sanders, of Toma¬ 
hawk Lake, for assistance in collecting; Mr. Bryant Walker, 
of Detroit, Michigan, and Dr. Y. Sterki, of New Philadelphia 1 , 
Ohio, for assistance in the determination of certain mollusks. 
GENERAL TOPOGRAPHY. 
Tomahawk Lake (plate XI) is situated on the line between 
Oneida and Villas counties. The drainage is into the Little 
Tomahawk River via Lake Kawaguesaga, a tributary of the 
Wisconsin River; the waters of this region, hence, belong to the 
Mississippi River drainage area. Tomahawk Lake is one of 
the numberous chains of lakes which dot this portion of the 
United States. It has been well said that no single area in the 
world includes so many lakes as does the country bordering the 
line between Canada and the United States, and Wisconsin may 
almost be said to lead in the number of its lakes, large and small. 
The lake under discussion is situated in the area covered by 
the late Wisconsin ice sheet and the multitude of ponds and 
lakes is due to the agency of this huge glacier. The lake is over 
four miles long and about two miles wide at its widest point; 
its many hays and coves give it a shore line of over eighty miles. 
It occupies a depression of some thirty to about one hundred 
feet below the surrounding country, the banks in many places 
rising quite abruptly. The country surrounding the lake was 
originally covered with a heavy coniferous forest, hut all that 
now remains is the area on the south side which has been set 
