MUSSELS OF WINONA, PIKE, AND CENTER LAKES. 3 I I 



It seems to us that the foregoing facts give basis for the fol- 

 lowing conclusions : the mussel zone lies mainly upon sandy and 

 gravelly banks, and on the outer edge of the same ; wave action 

 and the muskrat determine the shoreward limit of the distri- 

 bution, and the character of the bottom is the principal factor 

 determining the outer boundary of the zone. 



THE MUSSELS OF PIKE AND CENTER LAKES/ 



My work in the summer of 1904 was carried on with the aid 

 of Mrs. Headlee and was simply a continuation of that of the 

 previous summer. We had two main objects in view in pursu- 

 ing this study further ; to determine which of the distributional 

 forces discovered in Winona lake may be essential, that is, may 

 apply to small fresh- water lakes in general ; to ascertain by 

 experiment the effect of black mud bottom conditions on mussel 

 life, and what species are most resistant. 



In pursuance of the first object we studied the mussel distri- 

 bution in Pike and Center lakes and I shall devote the following 

 paragraphs to a brief discussion of them. 



In Center Lake we have Winona in miniature. Some new 

 elements, however, enter in the form of sewage-like shore wash- 

 ings on the southeast side and the absence of Potamogeton 

 patches and of heavy wave action. 



In general, I may say that the mussels here are much fewer 

 as compared with the number in Winona than the difference in 

 the sizes of the lakes would warrant. There are two conditions 

 here which may safely be regarded as at least partial explana- 

 tions of this difference : the southeast shore, which once sup- 

 ported great numbers, has become unfavorable to mussel life 

 through the accummulation of decaying vegetable and faecal 

 matter ; there is an enormous destruction by the small boy, who 

 finds amusement in collecting mussels to throw or to cut open 

 for pearls. 



Such mussels as are found, all varieties of U. Inteolus, U. sub- 

 rostratiis, U. rubiginosus and A. grandis, appear in situations in 



1 Pike and Center are two small lakes within two miles of Lake Winona and at 

 the very edge of the town of Warsaw, Indiana. 



