238 Proceedings of Indiana Academy of Science 
SUMMARY. 
Headlee and Simonton’s survey of Winona Lake, Evermann and 
Clark’s of Maxinkuckee, and Baker’s of Oneida show great similarity in 
the mussel distribution. The first named authors ascribe the limitation 
of mussel beds in their narrow shore zone to the encroachment of 
enemies, to wave action, and to the character of the bottom. The writer 
finds that enemies are of less importance in Winona Lake than formerly, 
yet the shoreward distribution continues to be held within bounds, that 
wave action is pertinent chiefly as a stimulus to movement, and that the 
character of the bottom is probably the most important of all dis- 
tributional factors. 
The present writer agrees with Headlee and Simonton in disregard- 
ing sex as a distributional factor, and to some extent age. Pressure 
incited certain more or less seasonal movements, and light is a stimulus 
to movement. 
Since the time of the foregoing paper on Winona Lake, much has 
been learned concerning the physical and chemical conditions of that 
body, the work chiefly of Scott. While the stimuli mentioned are largely 
responsible for confining the lake mussels to their narrow zone, yet the 
deeper parts of the lake are much less habitable to freshwater mussels 
for reasons which were necessarily disregarded in 1903. Due to the 
thermocline the conditions of temperature and dissolved gases are 
both unfavorable to mussel life. Furthermore the food supply is prin- 
cipally confined to the epilimnion, which bathes the lake bottom only 
along the shore. 
A set of experiments show that the movements in creeks of mussels 
transplanted from the lake are due both to pressure and to current, the 
latter chiefly directive. 
Municipal University of Akron, Ohio. 
LITERATURE CITED. 
Allen, W. R. The Food and Feeding Habits of Freshwater Mussels. Biological Bulle- 
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Studies of the Biology of Freshwater Mussels. I. Experimental Studies of 
the Food Relations of Certain Unionidae. Biol. Bull. 1921; 40; 210-241. 
Studies of the Biology of Freshwater Mussels. II. The Nature and Degree 
of Response to Physical and Chemical Stimuli. Ready. (The present paper forms No. 
III of this series.) 
Call, R. E. The Mollusca of Indiana. Ind. Dept. Geol. and Nat. Res. Rept. 1899; 
24; 335-535. 
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Acad. Sei. 1917; 251-285. 
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Ohio. Ann. Carnegie Mus. 1919; 8; 145-182. 2pl. 
Headlee, T. J. and Simonton, J. Ecological Notes on the Mussels of Winona Lake. 
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Isely, F. B. Experimental Study of the Growth and Migration of Fresh Water 
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Needham, J. G. and Lloyd, J. T. The Life of Inland Waters. 1916. Ithaca, p. 438. 
Scott, W. Report on the Lakes of the Tippecanoe Basin. Ind. Univ. Studies. 1916; 
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Simpson, C. T. Synopsis of the Naiades or Pearly Fresh Water Mussels. Proce. U. S. 
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