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A CONTRIBUTION TO A KNO^WLEDGE] OF INDIANA MOLLUSCA. 

 By R. Ellsworth Call. 



The wonderful diversity of physical features in Indiana contributes to 

 the development of an interesting molluscan fauna. Swamp, pond, creek 

 and river each presents forms or groups of forms characteristic of such 

 stations ; hillside, river bottom, prairie, contributes each its own peculiar 

 species. So that in a state of such widely different natural conditions it 

 is not surprising that a great array of forms, most of which are by no 

 means conspicuous, should have been discovered. 



There has never been made a geographic study, within this state, of its 

 mollusks. Nor have systematic collections ever been made of so much as 

 even a single stream. One could name on the fingers of the hands the 

 men and the places which have thus far yielded our sole knowledge of 

 Indiana mollusks. It is the object of this paper to state, in a few words, 

 the present condition of our information in this line and to indicate if 

 possible, the direction along which future effort should be made. 



It does not need words of mine to demonstrate that the first essential 

 condition to a complete study of the geographic distribution of Indiana 

 mollusca lies in complete and painstaking local collections. This is not 

 the task of a week nor of a single season. The habits of our mollusks are 

 so peculiar that certain seasons present sometimes many forms which fail 

 to appear again for several successive years. Often, even in the case of 

 the most common species, numbers of individuals are spasmodically great ; 

 then years go on and few of certain forms are to be found. No less in- 

 teresting will be the life history of these retiring animals. Not the life 

 history of a single Indiana species is known. And, so far as my informa- 

 tion goes, there is not a student in the state who is doing more than col- 

 lect the pretty and variously ornamented shells that they may grace a 

 cabinet! What their biological significance may be in that great sum 

 which makes^ up the animal life of Indiana no one seems to be investiga- 

 ting. 



A further necessity for immediate action that the original inhabitants 

 of the state may be listed lies in the danger of extinction of very manv 

 forms. The sewerage of towns and villages, the refuse of factories and 

 other manufacturing plants, the gradual encroachment on the primitive 

 forests, the drying up of streams, the drainage of swamps, the general in- 

 crease in tilled lands, these all conspire against the chances of perpetuity 

 of a rich molluscan fauna. What is done must be systematically done 



